Name	Info	Provider	Link
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=17636519.ui
	subscription/membership/fee required	Wiley	https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0007-1323&date=2007&volume=94&issue=8&spage=1041
	subscription/membership/fee required	Silverchair Information Systems	https://academic.oup.com/bjs/article-lookup/doi/10.1002/bjs.5971