1. WHO, UNICEF, UNFPA, World Bank Group, United Nations Population Division. Trends in maternal mortality: 1990 to 2015. Estimates by WHO, UNICEF, UNFPA, World Bank Group and the United Nations Population Division; 2015 [cited 15 December 2015] [Internet]. Geneva: World Health Organization. http://apps.who.int/iris/bitstream/10665/194254/1/9789241565141_eng.pdf?ua=1.
2. Maternal mortality for 181 countries, 1980–2008: a systematic analysis of progress towards Millennium Development Goal 5;MC Hogan;Lancet,2010
3. WHO. The global strategy for women’s, children’s and adolescents’ health (2016–2030); 2015 [cited 15 April 2016] [Internet]. Italy: Every Woman Every Child. http://who.int/life-course/partners/global-strategy/globalstrategyreport2016-2030-lowres.pdf?ua=1.
4. WHO. Strategies toward ending preventable maternal mortlaity (EPMM); 2015 [cited 15 April 2016] [Internet]. Geneva: World Health Organization. http://apps.who.int/iris/bitstream/10665/153544/1/9789241508483_eng.pdf?ua=1.
5. Maternal deaths: initial report of an on-going monitoring of maternal deaths at the Federal Medical Centre Katsina, Northwest Nigeria;BO Okusanya;J Matern Fetal Neonatal Med,2013