1. Trends in Maternal Mortality 1990 to 2015: estimates by the WHO, UNICEF, UNFPA, the World Bank and the United Nations Population Division;WHO, UNICEF, UNFPA, the World Bank, the United Nations Population Division,2015
2. World Health Statistics 2015;World Health Organization,2015
3. World Health Statistics 2016: Monitoring Health for the Sustainable Development Goals SDGs;World Health Organization,2016