"Age-Specific Study Guide for 18 Years Through Late Adulthood" Online Posting. 5 June 2003.<www.firstat.com/AGESG_18toAH.htm>
Berk, L. Development through the lifespan. (2nd ed.). Allyn and Bacon: Needham Heights, MA. (2001).
Bigner, Jerry J. "Middle Adulthood" Online Posting. Middle Adulthood. 1999. 4 June 2003. <http://lamar.colostate.edu/~bigner/MiddleAdult.html>
Build-A-Button. "Middle Age" Online Posting. Middle Age Quotes from Build-A-Button. 4 June 2003. <http://members.aol.com/BuildaButton/middleage.htm>
Lang, Susan. "CU researcher finds 'midlife crisis' is less common than many believe" Online Posting. Midlife Crisis is Less Common Than Many believe. 22 March 2001. 4 June 2003.<http://www.news.cornell.edu/Chronicle/01/3.22.01/midlife_crisis.html>
Planned Parenthood Federation of America, Inc. "Planned Parenthood Federation of America" Online Posting. Planned Parenthood Federation of America. 2003. 5 June 2003.<www.plannedparenthood.org>