Name	Info	Provider	Link
	subscription/membership/fee required	Ingenta plc	https://www.ingentaconnect.com/openurl?genre=article&issn=&volume=141&issue=2&spage=353&aulast=Yuan
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=38718376.ui
	subscription/membership/fee required	Silverchair Information Systems	https://pubs.asahq.org/anesthesiology/article-lookup/doi/10.1097/ALN.0000000000005043