The Lancet Global Health, Volume 6, No. 9, Year 2018
BMJ Global Health, Volume 5, No. 9, Year 2020
PLoS ONE, Volume 3, No. 7, Year 2008
BMC Pregnancy and Childbirth, Volume 21, No. 1, Year 2021
Bulletin of the World Health Organization, Volume 88, No. 10, Year 2010