Name	Info	Provider	Link
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=31393518.ui
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/31393518/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/31393518
	subscription/membership/fee required	Silverchair Information Systems	https://jamanetwork.com/journals/jamaoncology/fullarticle/10.1001/jamaoncol.2019.1856