As a stockholder, would you prefer a CEO who is strictly rational about her firm’s future prospects, or a CEO who is somewhat overoptimistic? Researchers at Texas A&M University show theoretically that for risk-averse CEOs, being somewhat overoptimistic is a good thing for shareholders.

Most CEOs are undiversified, meaning that a large fraction of their personal wealth is in invested their company. Stockholders, on the other hand, are typically well diversified, with investments across numerous companies. These differences mean that a risk-averse CEO who is strictly rational will turn down some risky investment projects that the stockholders would like the firm to make. If this happens, the result is lower firm value.

“Given a choice between a very rational CEO and a moderately overoptimistic one,” says Mays finance professor Shane Johnson, “the somewhat overoptimistic one is the better choice.”

“We show theoretically that overoptimism can help offset the effect of the CEO’s risk aversion,” Texas A&M finance professor Shane Johnson says. “The result is that a CEO who is moderately overoptimistic will invest the way shareholders would want her to invest—this maximizes firm value.” In contrast, a purely rational CEO turns down too many investment projects relative to the optimal level, whereas a CEO who is too overoptimistic accepts too many investment projects. Both underinvestment and overinvestment produce firm values below what it could be.

“If the theory is correct, CEOs who are somewhat overoptimistic should face a lower probability of termination than rational CEOs or too-overoptimistic CEOs face. A board doesn’t necessarily know a CEO’s level of optimism when it hires her. It learns by watching his decisions over time,” Johnson says. If CEOs who are somewhat overoptimistic maximize firm value, they should be more likely to keep their jobs than would CEOs with too-low or too-high optimism. Using a large sample of CEO terminations, the team finds strong empirical support for the theoretical predictions. The results are consistent with the view that CEOs who are somewhat overoptimistic maximize firm value.

Before this research was conducted, the common belief was that any level of over-optimism was bad, says Johnson. “Our paper is one of a series that argues that some level of over-optimism is good for CEOs,” he says. “Given a choice between a very rational CEO and a moderately overoptimistic one, the somewhat overoptimistic one is the better choice.”

The research was conducted by Texas A&M finance professor Shane Johnson; doctoral students T. Colin Campbell, Jessica Rutherford and Brooke Stanley; and former Texas A&M professor Michael Gallmeyer, who is at the University of Virginia.

For more information, contact Johnson at

“CEO Optimism and Forced Turnover” by T. Colin Campbell, Michael Gallmeyer, Shane A. Johnson, Jessica Rutherford and Brooke W. Stanley was published in Journal of Financial Economics.

Categories: Research Notes

Intuitively, it is clear that changes in a service environment can reduce the quality of a service at least temporarily. But what is not clear is how deeply, and for how long, major changes affect operating performance – that is, until Texas A&M University business professors Gregory Heim and Michael Ketzenberg decided to answer those questions. They chose a dramatic example of redesign and decided to focus on experience-based service companies, in general, and an area that had not been previously studied in depth: golf courses.

“The argument for improving a course is to make it better, but we wanted to find out if people really thought that was true,” said Mays professor Gregory Heim. “Some people embrace change, while others don’t.”

Many service managers redesign their services periodically to keep their offerings fresh, competitive and desirable to customers. Prior research has shown that it could increase repeat business. What Heim and Ketzenberg wondered was how service firm managers and employees relearn to improve their performance after these major redesigns.

That was the extent of Heim’s golf knowledge at the start of this project. He sought out a colleague to fill the gaps. He did not have to search far to find someone to fit the bill. In fact, Ketzenberg was just down the hall. Ketzenberbg has two passions: research and golf, and he considers the opportunity to combine both a godsend. Heim says he focused on the data analysis, while Ketzenberg provided golfing expertise. “It was an ideal pairing for this project,” Heim says.

Heim says a major research challenge is obtaining real-world operating data from companies upon which to base the research. Most companies are reluctant to share their data. For this study, the authors were looking for data from multiple companies over multiple years. Golf courses posed less of a problem, since the data were publicly reported.

Gregory Heim

The data came in the form of “panel data” from The Dallas Morning News. The News tracks the top Texas golf courses annually through ratings and evaluations of top courses by golf professionals, as well as information on when the courses were designed and redesigned. Heim and Ketzenberg chose to study the data from 1989 to 2009. Their study provides managerial insight by demonstrating the extent of learning, illustrating how redesigns can negatively affect service outcomes, showing how relearning occurs and discussing tactics for success when redesigning services.

Major redesigns, intended to improve products and services, tend to throw the quality of service off track, the researchers found. The question was how long the service suffers, which they studied through learning effect patterns during routine operation periods as well as “window of opportunity” effects the local service crews felt after outside firms had completed the major redesigns.

“We wanted to see what we could learn about what happens when you destroy the course to redesign it; how age affects the long-term experience; and whether the quality of service gets better with time,” says Heim. “When you redesign it, there’s a period of time when the customers miss the familiar old course and they have to re-learn to navigate the course — the hazards, slope of the course, shape of the greens, and so forth. The argument for improving a course is to make it better, but we wanted to find out if people really thought that was true. Some people embrace change, while others don’t.”

Michael Ketzenberg

The topic is a nontraditional one for the field of information and operations management, but both of them say it was fun to do. The lessons learned were to carefully consider changes, communicate about them with stakeholders and make the investment in training staff for the transition. “Discontinuous events that lead to dissatisfaction on the customer’s part are not going to pan out to be good investments,” Heim says.

Both Texas A&M researchers plan to continue golf-related research: Heim intends to update the golf data for new studies while Ketzenberg is working with Rogelio Oliva and a colleague from Europe, Mozart Menezes, on a paper titled “Optimal Scheduling of Golf Beverage Carts.” Ketzenberg explains, “We are trying to answer the often-heard golfer’s lament of why there is never a beverage cart around when you want one. Fun stuff.”

For more information, contact Heim at or Ketzenberg at

The paper “Learning and Relearning Effects with Innovative Service Designs: An Analysis of Top Golf Courses” by Heim and Ketzenberg was released in July 2011 in Journal of Operations Management.

Categories: Research Notes

It’s complicated, an employee’s decision to leave a job — even more complicated than previously believed, Texas A&M University researchers conclude after conducting research on when job searches result in turnover.

As expected, turnover was higher when employees had lower levels of embeddedness and job satisfaction and higher levels of available alternatives. What wasn’t expected, or previously explained, was that there is more complexity to the process than believed, and specifically, that these factors play a key role in whether search behavior actually results in the decision to quit.

Wendy Boswell

Embeddedness means how attached someone is to his current environment, says Mays Business School faculty member Wendy Boswell, who collaborated on the research with fellow faculty member Ryan Zimmerman and doctoral candidate Brian Swider. The trio examined factors that may help explain under what conditions employee job search effort may most strongly (or weakly) predict subsequent turnover.

“How tied you are to not only the place but also the community — if you own a home, your spouse has a job there, you belong to a church or are involved in schools, determines how much incentive it takes to get you to leave,” Boswell explains.

“Fit” is also important — whether the values of a community (as well as the organization) align with the individual’s — and characteristics such as metropolitan versus small-town, or urban versus industrial. “The practical implication for an employer is to know who is really vulnerable to leaving, then going and intercepting those high performers — retention isn’t “one size fits all,'” explains Boswell.

Ryan Zimmerman

The culture of the organization and community also carry great weight in the decision, Swider says. “Say I’m working in New York City and a job opens in a small southern suburb. Whether I pursue that opportunity depends on my personal preferences,” Swider says. “It could be the opportunity I’ve been waiting for or it could sound like a nightmare.”

Employers do a poor job of predicting impending turnover, Swider says. These findings suggest that there may be a number of factors interacting to influence employees’ turnover decisions, indicating greater complexity to the process than described in previous prominent sequential turnover models.

Boswell explains the assumed process: An employee experiencing job dissatisfaction searches for alternatives, evaluates them against his current position, then either quits or stays put. But, often times, employees search and don’t leave. Online applications make it easier to search and even apply for positions, but the likelihood of an employee actually accepting another position depends on his level of enmeshment or “stuckness” as well as how important it is for the person to leave and whether he or she even has the opportunity.

Brian Swider

“The more of these attachments you have, the more likely you are to want to stay somewhere,” Boswell explains. “It used to be the defined benefit plan, but now it is all these other factors that you might have to sacrifice if you were to leave.”

The key for an employer to stay ahead of the turnover, Boswell says, is to know his or her employees. “Are they satisfied, embedded, on the fence?” she says. “Are they flight risks? If so, and if they are top employees, you might be wise to invest in trying to retain them.”

For more information, contact Swider at or Boswell at

“Examining the job search – turnover link: The role of embeddedness, job satisfaction, and available alternatives,” by Brian W. Swider, Wendy R. Boswell, and Ryan D. Zimmerman, was published in the March 2011 issue of the Journal of Applied Psychology.

Categories: Research Notes

Imagine borrowing from someone else’s stockpile of corporate stocks, then selling shares, later buying them back and returning them, keeping any profit. That’s what short sellers do on a regular basis, and they tend to out-perform the analysts.

The practice is called short selling, and research by two Texas A&M University business professors and a former PhD student shows that ordinary investors can profit by trading with the short sellers.

Lynn Rees

Their research investigated whether short sellers and analysts differ in how they use information that predicts future returns. It appears short interest significantly anticipates the expected direction, while analysts tend to positively recommend stocks with high growth, high accruals, and low book-to-market ratios, despite these variables having a negative association with future returns.

“Investors frequently observe and use recommendations from analysts on whether to buy or sell a stock,” says accounting Professor Lynn Rees. “But, our research suggests that analysts do not always use accounting information, such as accounting accruals and cash flows, in forming their recommendations; whereas, short sellers appear to do much better in using these signals.”

Co-authors are Edward P. Swanson, holder of the Durst Chair in Accounting; and Mays doctoral graduate Michael Drake of BYU. The researchers have presented the paper to professionals, as well as academic audiences, and a NYC capital management company that uses short interest as an input in an investment model.

Edward Swanson

A low percentage of investors do short selling, but a very high percentage of investors would be interested in what they are doing, Rees says, because the short sellers tend to do better than the market. “Our evidence suggests that using the level of short interest combined with analysts’ forecasts allows investors to make more profitable investment decisions,” he says.

For more information about this research, contact Rees at, or Swanson at

“Trading against the prophets: Using short interest to profit from analyst recommendations,” by Michael Drake, Lynn Rees and Edward P. Swanson, was published in The Accounting Review.

Categories: Research Notes

Businesses competing with larger companies — particularly those that enter a market by acquiring an established business — will fare better if they differentiate themselves from the “behemoths” rather than imitate them or take them head-on, suggests research on the topic.

The researchers found that competitors who imitated the large newcomer had poorer performance, which was counter to prior research.

Alina Sorescu

The phenomenon of acquiring a company to enter a marketplace — common in banking, pharmaceuticals and technology — hasn’t been studied as thoroughly as the path companies take to enter a market through other means, such as introducing a new product, says Alina Sorescu, an associate professor of marketing and Mays Research Fellow.

She and several other researchers tackled the topic in the paper “Behemoths at the Gate: How Incumbents Take On Acquisitive Entrants (And Why Some Do Better Than Others),” which has been accepted for publication in Journal of Marketing.

The research was centered on the banking industry because firms and the actions they take in this industry are well documented, Sorescu says. The researchers looked at 1995-2003 bank data from the FDIC, such as deposit summaries, and interviewed banking officials. The data covers 839 acquisitions in 583 Metropolitan Statistical Areas in the U.S. banking industry. The research specifically focuses on how banks modify their product mix when a large bank enters their market through an acquisition. In this context, the product mix of banks includes various types of loans such as, for instance, commercial and industrial loans and loans secured by real estate. Changes in product mix were assessed at the two-year and three-year marks after the acquisitions.

Results indicate that incumbents are more likely to align their product mix strategy with that of the behemoth if: (1) the incumbent is large; (2) the behemoth’s past performance has been strong; and (3) the market served by the incumbent is small. The size of the market tends to set the tone of the competition, Sorescu says. “The smaller the market, the more likely the incumbent is to imitate the acquirer,” she observes. “It’s like a big fish in a small pond making a big splash — they compete with the same small base of customers.”

Sorescu concludes it’s a bad idea to go head-on with the acquirer.

“It’s best to try to diverge from the acquiring company, even though it is a threatening presence and it is tempting to try to mimic what it is doing,” she says. “You assume the larger corporations have identified a strong path and an advisable product mix, but you must differentiate yourself from it in order to survive. The small firms that imitate the large firms may not be able to offer the same products and services as efficiently as large firms do, and they could suffer more harm than if they focused on what they already do well.”

For more information, contact Sorescu at

The research paper, “Behemoths at the Gate: How Incumbents Take On Acquisitive Entrants (And Why Some Do Better Than Others),” was in press in late 2011 at Journal of Marketing.

It is a collaboration among Alina Sorescu, Prokriti Mukherji, Jaideep Prabhu and Rajesh Chandy. Prokriti Mukherji is senior research associate at the Carlson School of Management, University of Minnesota. Jaideep Prabhu is Jawaharlal Nehru Professor of Indian Business at Judge Business School, University of Cambridge. Rajesh Chandy is Professor of Marketing and Tony and Maureen Wheeler Chair in Entrepreneurship at London Business School.

Categories: Research Notes

Bootlegged concert recordings, undocumented immigrants building houses in the U.S., New York City street vendors selling designer knock-offs—these are examples of a largely unexamined economic activity, the informal economy. These economic activities are considered illegal yet still viewed as socially acceptable or legitimate by some substantial segment of society.

Because nearly nine percent of the GDP of the United States (and perhaps more than 60 percent in some African and South American countries) is involved in the informal economy, it is a topic worth exploring, says Duane Ireland, Distinguished Professor of Management and Conn Chair in New Ventures Leadership. He and two Mays colleagues (David Sirmon and Laszlo Tihanyi) and Justin Webb (a recent graduate of the Mays Ph.D. program who is now at Oklahoma State University) have examined how the informal economy works and the reasons some ventures thrive, despite barriers of legality and legitimacy.

The illegality of bootleg DVDs in most countries has not prevented them from becoming a significant source of income for many entrepreneurs willing to take the risk of operating in an informal economy.
The illegality of bootleg DVDs in most countries has not prevented them from becoming a significant source of income for many entrepreneurs willing to take the risk of operating in an informal economy.

The cornerstone of their research is a matrix for categorizing entrepreneurial activities based upon legality and legitimacy. While some entrepreneurial activities in the informal economy are considered illegal yet legitimate (e.g., the sale of counterfeit products or use of undocumented workers as labor to build a home), other entrepreneurial activities fit different classifications of legality and legitimacy. For example, tobacco-based and adult-oriented products in the United States are legal yet considered illegitimate by large societal groups.

In contrast, illegal drugs and human trafficking are considered illegitimate by the overarching society. Distinguishing among different classifications of legality and legitimacy is important to understanding the mechanisms through which these entrepreneurial activities are able to exist, grow, and be sustained even while occurring outside of the law.

Ireland says one aspect that he finds fascinating is how a business can move between categories over time, due to the intentional actions of the business or due to shifts in the definitions of legality and legitimacy. Take for instance, alcohol sales in the United States in the 1920s during prohibition. Though it was illegal, speakeasies and bootlegged liquor became quite commonplace and legitimate. Then in 1933, the industry once again was legalized. This is a great example of the fluid nature of the boundaries in this area.

In a similar vein, the production of marijuana is an example of the porous nature of the matrix, as it is moving from illegal and illegitimate in the United States to illegal but legitimate, or legal but illegitimate, depending on some groups’ norms, values, and beliefs and various state and local laws.

Another example is Napster ten years ago and during its initial operations. It was alleged that Napster allowed users to violate copyright laws by sharing audio files freely. The online service was hugely successful from 1999 to 2001 when it was shut down due to issues of legality. At least initially, similar allegations suggest that Youtube violated copyright laws by not removing items from its site that were posted by individuals who did not have permission from the owners of the postings. However, for some large groups and with an increasing expectation of free content on the Internet, Youtube is still seen as legitimate, despite the fact that some postings may not be legal with respect to copyright laws.

The paper “You say illegal, I say legitimate: entrepreneurship in the informal economy,” appeared in Academy of Management Review in 2009 and was a finalist for best paper that year.

Categories: Research Notes

Toward the end of their relationship, Enron was paying nearly $50 million each year to Arthur Andersen for services, including both internal and external audit functions. Did the risk of losing such a large client lead to the ethical compromises that Andersen was willing to make in colluding in the enormous fraud scandal that eventually brought down both firms?

Nathan Sharp

Yes, said analysts, who recommended internal and external audit functions in public companies be split between firms to prevent economic bonding and cooperation in fraud. Created soon after, the Sarbanes-Oxley Act prohibited external audit firms of public companies from having any involvement in the internal audit function. However, research from Nathan Sharp, assistant professor of accounting, suggests this move may have been a mistake.

Sharp and colleagues investigated companies in the pre-SOX era to determine if companies that outsourced or co-sourced internal audit work to their external auditor had a higher risk of misleading or fraudulent external financial reporting. The result? This relationship actually lowered accounting risk.

The reason is simple. When a single firm is involved in both audits, it’s harder for fraud to go undetected, as there is greater communication between both audit teams. Knowledge spillover occurs because the internal audit team provides insights into the company that an external audit team might miss. This information sharing is less likely to happen when the teams are from competing firms or when the internal audit function is kept entirely in-house.

There is much debate about this topic says Sharp, and he and his colleagues are not suggesting SOX be changed. However, if you talk to public accounting firms, the opinions are clear: It’s good sense to make it easier to share information between internal and external audit teams to create the most complete financial snapshot of a company.

Sharp’s article, “Internal Audit Outsourcing and the Risk of Misleading or Fraudulent Financial Reporting: Did Sarbanes-Oxley Get It Wrong?” coauthored with Doug Prawitt and David Wood, is currently under review at Contemporary Accounting Review.

Categories: Research Notes

When you hear of corporate scandals, you might assume that the perpetrators of the crime were acting out of self-interest—that they cooked the books or covered up information to get rich or move up the corporate ladder. But what if there was another motivation that has nothing to do with personal gain?

A recent study from Elizabeth Umphress, associate professor of management and Mays research fellow, looks at motivations for unethical behavior that benefits the corporation (called “unethical pro-organizational behavior,” or UPB) and how it may be tied to the degree of organizational identification the individual feels.

The researchers define UPB as activity that is not specified by formal job descriptions; is either illegal or morally unacceptable to the larger community; and includes acts of commission (e.g. cooking numbers to boost analyst projections and stock values) and omission (e.g., withholding information about the hazards of a pharmaceutical product).

In three studies Umphress and colleagues conducted, the results were consistent: there was not a direct relationship between organizational identification and UPB. However, there was a relationship between the two if a third element, positive reciprocity, was involved.

Findings indicate that if an individual feels a need to reciprocate when something has been done for them, and also strongly identifies with the organization, then they are more likely to commit UPB. Employees who strongly identify with their organization feel obligated to protect and maintain their membership in the organization.

They also find that people can be primed to commit UPBs—when they showed a test group a video that enhanced their feeling of organizational identification, they were more likely to agree to UPBs (if they scored highly on measures of positive reciprocity) than those who had seen an unrelated video.

Both organizational identification and positive reciprocity are good traits for an employee to possess, says Umphress. They can make an employee more diligent, productive and loyal. Managers need to be aware, however, that they can interact in this negative way. Umphress stressed that hiring decisions need not be made on this criteria, but that managers should be aware of the degree of these traits in their employees and understand that in the right circumstance “the employee might feel compelled or feel that it’s their duty to do something unethical…to help protect the organization.”

In previous literature, researchers have focused predominately not on unethical behavior that boosted the organization, but rather behavior that harms it, such as stealing or sabotage. This study is one of the first to examine this unique relationship.

Umphress’s article, “Unethical behavior in the name of the company: the moderating effect of organizational identification and positive reciprocity beliefs on unethical pro-organizational behavior,” written with coauthors Marie Mitchell and John Bingham, appeared in Journal of Applied Psychology in 2010.

Categories: Faculty, Research Notes

Employee wellness programs have often been viewed as a nice extra, not a strategic imperative. But the data demonstrate otherwise, according to a team of researchers led by Leonard L. Berry of Mays Business School at Texas A&M University, Ann M. Mirabito of Baylor University and William B. Baun of the University of Texas MD Anderson Cancer Center.

Their research shows that the return on investment on comprehensive, well-run employee wellness programs is impressive — sometimes as high as six to one.

Leonard Berry

The findings are compiled in a comprehensive piece in the December issue of Harvard Business Review titled “What’s the Hard Return on Employee Wellness Programs?” The subhead reads, “The ROI data will surprise you, and the softer evidence may inspire you.”

To achieve those kinds of results, employers cannot merely offer workers a few passes to a fitness center and nutrition information in the cafeteria, the team reports. The most successful wellness programs are supported by six essential pillars: engaged leadership at multiple levels; strategic alignment with the company’s identity and aspirations; a design that is broad in scope and high in relevance and quality; broad accessibility; internal and external partnerships; and effective communications, Berry says.

The team studied 10 organizations that have financially sound workplace wellness programs. They conducted interviews with senior executives, managers of health-related functions and focus groups of middle managers and employees — in all, about 300 people. The team found companies in a variety of industries — including Johnson & Johnson, Lowe’s, H-E-B and Healthwise — have built their employee wellness programs on all six pillars and have reaped big rewards in the form of lower costs, greater productivity and higher morale. Those benefits are not easy to achieve, and verifiable paybacks are never a certainty, but the track record inspires emulation, especially when the numbers are studied, the report states.

Behind the research are Berry, the Presidential Professor for Teaching Excellence who also holds the rank of Distinguished Professor of Marketing as well as the M.B. Zale Chair in Retailing and Marketing Leadership at Mays Business School at Texas A&M ; Mirabito, an assistant professor of marketing at the Hankamer School of Business at Baylor; and Baun, manager of the wellness program at the MD Anderson Cancer Center, a director of the National Wellness Institute and a director of the International Association for Worksite Health Promotion.

Berry has spent more than 30 years studying corporate service quality, and conducted an in-depth service study of the Mayo Clinic to uncover fresh and innovative approaches to serving  patients. He also serves as a Professor of Humanities in Medicine in the College of Medicine at The Texas A&M University System Health Science Center.

Categories: Research Notes

Two things can dramatically decrease the level of pollution likely to be created by a firm, says new research. No, it’s not complicated machinery for carbon sequestration, or more government regulation. It’s much simpler: family ownership and financial rewards.

Luis Gomez-Mejia

New research suggests that firms where a single family owns at least five percent of the voting stock, pollution levels are much lower. Also, firms pollute less when the CEO is given long-term financial incentives for pollution control.

To come to these results, researchers analyzed toxic emission reports from the Environmental Protection Agency, examining the structure and actions of hundreds of companies.

When it comes to family ownership, researchers hypothesize that when a family’s image and reputation are at stake, there is a greater drive to be ecologically sound. Institutional investors can tend to have a more short-term view of the business, while family owners are more concerned with its overall quality and longevity, says Luis Gomez-Mejia, the Benton Cocanougher Chair in Business and Mays management professor, who has co-authored two studies on the topic of corporate pollution reduction.

Other research on family-owned firms and “socio-emotional wealth” dovetails with Gomez-Mejia’s: leaders of family-owned companies are more likely to derive a sense of identity from the firm, desire to be seen as generous and pro-social within a community, and strive to maintain group integrity within a community.

These factors create a non-economic incentive for environmental efficacy, particularly if the family and the business are concentrated in one location as the family usually cannot escape being the face of the business.

When firms are not family owned, Gomez-Mejia says corporate pollution reduction is still a matter of incentives; however this time, the incentive is financial rather than socio-emotional. “To the extent that the CEO is rewarded for investing in pollution control and also pollution prevention, the more likely it is that the firm will engage in those efforts,” he says.

Furthermore, the structure of the incentives matter: stock and option incentives are more effective than cash in pollution reduction. This is due to the long-term nature of both meaningful environmental policies and the interest-bearing securities. That is, continued pollution control leads to continued corporate wellbeing, which leads to continued growth of securities held by the CEO.

Gomez-Mejia admits there is one limitation to the research: the EPA only requires emission reports for American companies and many of the corporations involved in the study are multinational. “A remaining question is to what extent…the CEOs may have an incentive to move or shift the pollution elsewhere,” he says. He is planning a follow-up study to investigate this question, but notes that data collection is difficult, as pollution reporting in many developing countries is not accurate.

“Socio-economic wealth and corporate responses to institutional pressures: Do family-controlled firms pollute less?” is a collaboration between Pascual Berrone, Cristina Cruz, Gomez-Mejia, and Martin Larraza-Kintana, published in Administrative Science Quarterly in 2010.

“Environmental performance and executive compensation: an integrated agency-institutional perspective,” is a collaboration between Pascual Berrone and Gomez-Mejia, published in the Academy of Management Journal in 2009.

Categories: Research Notes