1. Deaths: final data for 2010. National vital statistics reports. Volume 61, number 4;Murphy,2013
2. Preterm birth: causes, consequences, and prevention,2007
3. 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
4. World Health Organization. Preterm birth fact sheet. Available at: http://www.who.int/mediacentre/factsheets/fs363/en. Accessed Aug. 14, 2014.
5. Behind international rankings of infant mortality: how the United States compares with Europe. NCHS data brief, no 23;MacDorman,2009