1. The Partnership for Maternal Newborn & Child Health, Save the Children, World Health Organization, Born Too Soon: The Global Action Report on Preterm Birth;March of Dimes,2012
2. National, regional, and worldwide estimates of preterm birth rates in the year 2010 with time trends since 1990 for selected countries: a systematic analysis and implications;Blencowe;Lancet,2012
3. Preterm Birth: Causes, Consequences, and Prevention;Committee on Understanding Premature Birth and Assuring Healthy Outcomes,2007
4. International Statistical Classification of Diseases and Related Health Problems, Tenth Revision;World Health Organization,2004
5. The worldwide incidence of preterm birth: a systematic review of maternal mortality and morbidity;Beck;Bull World Health Organ,2010