Periodic abstinence and calendar method use in Hungary, Peru, the Philippines, and Sri Lanka¹

References 

1. Curtis SL, Neitzel KN. Demographic and health surveys comparative studies no. 19, contraceptive knowledge, use and sources. Calverton, MA: Macro International; 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 Statistics Office (NSO) The Department of Health, Philippines, and Macro International (MI) . National demographic, and health survey 1998. Manila, Philippines: NSO and MI; 1999;
4. Department of Census and Statistics, Sri Lanka . Sri Lanka demographic and health survey 1993. Colombo, Sri Lanka: Department of Census and Statistics; 1995;
5. Bertrand JT, Brown JE, Ward VM. Techniques for analyzing focus group data. Evalua Rev. 1992;16:198–209
6. Debus M. Methodological review (handbook for excellence in focus group research). Washington, DC: Academy for Educational Development; 1990;
7. Hatcher R, Trussell J, Stewart F, et al.  Contraceptive technology. 16^th ed.. New York: Irvington; 1994;
8. Hermann, CB, Williamson NE, McCann M, et al. Periodic abstinence in developing countries: update and policy options. Research Triangle Park, NC: Family Health International, June 1986.