Name	Info	Provider	Link
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=11169051.ui
	subscription/membership/fee required	Wiley	https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0266-8254&date=2001&volume=32&issue=2&spage=99
	subscription/membership/fee required	Silverchair Information Systems	https://academic.oup.com/lambio/article-lookup/doi/10.1046/j.1472-765x.2001.00862.x