Name	Info	Provider	Link
	free resource	BioMed Central	https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/1471-2393-7-12
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/17623077/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/17623077