Name	Info	Provider	Link
	subscription/membership/fee required	Atypon	https://journals.sagepub.com/doi/10.231/JIM.0b013e318202a9db?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub 0pubmed
	subscription/membership/fee required	HighWire	https://jim.bmj.com/lookup/pmidlookup?view=long&pmid=21099701
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=21099701.ui