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3. Singh S, Sedgh G, Hussain R: Levels and trends in unintended pregnancy worldwide. paper presented at the annual meeting of the Population Association of America, Detroit, MI, USA, April 30th –May 2nd. 2009
4. Singh S, Wulf D, Hussain R, Bankole A, Sedgh G: Abortion Worldwide: A Decade of Uneven Progress. 2009, New York: Guttmacher Institute
5. Guttmacher Institute, et al: Special analyses. Adding It Up: The Costs and Benefits of Investing in Family Planning and Maternal and Newborn Health. Edited by: Singh S. 2009, New York: Guttmacher Institute and United Nations Population Fund