Bureau of Labor Statistics, U.S. Department of Labor. Occupational Outlook Handbook. 2006-07 Edition. Psychologists. retrieved from http://www.bls.gov/oco/ocos056.htm (页面存档备份,存于互联网档案馆) on June 30, 2006.
Bureau of Labor Statistics, U.S. Department of Labor. Occupational Outlook Handbook. 2006-07 Edition. Psychologists. retrieved from http://www.bls.gov/oco/ocos056.htm (页面存档备份,存于互联网档案馆) on June 30, 2006.