1. United Nations . Trends in Contraceptive Use Worldwide 2015. United Nations: New York, 2015.
2. Adding it up: investing in contraception and maternal and newborn health in Nigeria, 2018. New York Guttmacher Institute; 2019.
3. Demand and unmet needs of contraception among sexually active in-union women in nigeria: distribution, associated characteristics, barriers, and program implications;Fagbamigbe;SAGE Open,2018
4. Singh S , Darroch JE , Ashford LS . Adding It Up: The Costs and Benefits of Investing in Sexual and Reproductive Health 2014. New York: UNFPA and Guttmacher Institute, 2014.
5. Cost and benefits of investing in contraceptive services in the developing world. New York: UNFPA and Guttmacher Institute; 2012. Available: https://www.guttmacher.org/sites/default/files/pdfs/pubs/FB-Costs-Benefits-Contraceptives.pdf