1. Demographic and health surveys comparative studies no. 19, contraceptive knowledge, use and sources;Curtis,1996
2. Intituto Nacional de Estadistica e Informa (INEI), and Macro International (MI). Encuesta demografica y de salud familiar 1996. Lima, Peru (INEI), and Columbia, MA (MI), 1997.
3. National demographic, and health survey 1998,1999
4. Sri Lanka demographic and health survey 1993,1995
5. Techniques for analyzing focus group data;Bertrand;Evalua Rev,1992