IM Spence-Lewis MD, 14 Mar 2017 http://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/s12884-015-0725-7
IM Spence-Lewis MD, 23 May 2016 http://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/s12884-015-0725-7