Smith H J, Portela A G, Marston C
Centre for Maternal and Newborn Health, Liverpool School of Tropical Medicine, Liverpool, UK.
Department of Maternal, Newborn, Child and Adolescent Health, World Health Organization, Geneva, Switzerland.
BMC Pregnancy Childbirth. 2017 Aug 31;17(1):280. doi: 10.1186/s12884-017-1450-1.