Gebreselassie, Tesfayi, Shea O. Rutstein, and Vinod Mishra. 2008. Contraceptive use, breastfeeding, amenorrhea and abstinence during the postpartum period: An analysis of four countries. DHS Analytical Studies No. 14. Calverton, Maryland, USA: Macro International. Available at http://dhsprogram.com/pubs/pdf/AS14/AS14.pdf.