1. International statistical classification of diseases and related health problems,2004
2. Definitions, rationale, concepts and sources. UN,2003
3. Global, regional, and national levels and trends in maternal mortality between 1990 and 2015, with scenario-based projections to 2030: a systematic analysis by the UN Maternal Mortality Estimation Inter-Agency Group. United Nations Maternal Mortality Estimation Inter-Agency Group collaborators; technical advisory group;L Alkema;Lancet,2015
4. Maternal mortality: only 42 days;L Hoj;BJOG Intenational Journal of obstetric and Gynecology,2003
5. Global, regional, and national levels and causes of maternal mortality during 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013;N Kassebaum;The Lancet,2014