U.S. Department of health and Human Services : Centers for Disease Control and Prevention. National Center for Chronic Disease Prevention and Health Promotion, division of Reproductive Health1999
by Gugulethu GuleAfrican Population and Environment Institute with assistance from Japan International Cooperation Agency, Population Education Promotion Project1994
Working Group on Factors Affecting Contraceptive Use, Panel on the Population Dynamics of Sub-Saharan Africa, Committee on Population, Commission on Behavioral and Social Sciences and Education, National Research CouncilNational Academy Press1993