Name	Info	Provider	Link
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22297442/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/22297442
	free resource	Pagepress Publications	https://doi.org/10.4081/ejh.2011.e36