1. Foreign postdocs: the changing face of biomedical science in the U.S;Garrison H. H.;FASEB J.,2005
2. National Science Foundation(2008)Table 14. Doctoral scientists and engineers on postdoctoral appointments by selected demographic characteristics and broad field of doctorate: 2008. InSurvey of Doctorate Recipients.Accessed September 16 2015 at:http://www.nsf.gov/statistics/nsf13302/content.cfm?pub_id=4214&id=2
3. National Science Foundation(2010)Table 77. Doctoral scientists and engineers employed as postdoctoral appointees by selected demographic characteristics and broad field of doctorate: 2010. InSurvey of Doctorate Recipients.Accessed September 16 2015 athttp://ncsesdata.nsf.gov/doctoratework/2010/html/SDR2010_DST77.html
4. U.S. Department of State Bureau of Consular Affairs(2015)Nonimmigrant visa statistics nonimmigrant worldwide issuance and refusal data by visa category. Accessed September 16 2015 at:http://travel.state.gov/content/visas/english/law‐and‐policy/statistics/non‐immigrant‐visas.html