The past week wasn't easy for Tang Jun, former president of Microsoft China and Shanda, and current CEO of the New Huadu Industrial Group. Tang was exposed to have received his doctoral degree from a university that was known to sell credentials - the California-based Pacific Western University.

In fact, there are a number of U.S. universities that have been found to sell credentials at different prices, which are known as diploma mills. The U.S. Government Accountability Office (GAO) published a list of such problematic universities in a report in 2004. Besides Pacific Western University, six other universities were confirmed as diploma mills, including Alabama-based Barrington University, Mississippi-based Lacrosse University, California-based California Coast University, Wyoming-based Hamilton University, California-based Kennedy-Western University, and Pennsylvania-based LaSalle University.

Back in 2001, Wu Zheng, former chairman of Sun Media Group and husband of renowned Chinese TV hostess and businesswoman Yang Lan, was exposed to have faked his doctoral credentials. Wu's doctoral degree was obtained at the Barrington University listed above.

According to Caixin Online, these diploma mills often use names that are similar to those of some regular universities. For example, the Wyoming-based Hamilton University is not recognized by the U.S. Department of Education. However, the Hamilton College in New York is a legal university approved by the U.S. regulator.

China's business press carried the story above on Monday. China.org.cn has not checked the stories and does not vouch for their accuracy.