Name	Info	Provider	Link
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=19608841.ui
	subscription/membership/fee required	Wolters Kluwer	https://doi.org/10.1213/ane.0b013e3181a909a4