Name	Info	Provider	Link
	subscription/membership/fee required	Ingenta plc	https://www.ingentaconnect.com/openurl?genre=article&issn=0148-5717&volume=51&issue=3&spage=199&aulast=Mullis
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=38100794.ui
	subscription/membership/fee required	Wolters Kluwer	https://doi.org/10.1097/OLQ.0000000000001911