Name	Info	Provider	Link
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=30694529.ui
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/30694529/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/30694529
	free resource	Wiley	https://onlinelibrary.wiley.com/doi/10.1002/cncr.31861