1. Smith JC. Abortion surveillance report, hospital abortions, annual summary 1969. Atlanta, GA: US Department of Health, Education, and Welfare, Public Health Service, Health Services and Mental Health Administration, National Communicable Disease Center; 1970.
2. Abortion surveillance—United States, 2005.;CDC;MMWR Surveill Summ,2008
3. Henshaw SK, Kost K. Trends in the characteristics of women obtaining abortions, 1974 to 2004. New York: Guttmacher Institute. Available at http://www.guttmacher.org/pubs/2008/09/23/TrendsWomenAbortions-wTables.pdf.
4. Trends in abortion in the United States.;Jones;Clin Obstet Gynecol,2009
5. Henshaw SK, Kost K. Abortion patients in 1994–1995: characteristics and contraceptive use. Fam Plann Perspect 1996;28:140–7, 58.