Name	Info	Provider	Link
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=21604067.ui
	subscription/membership/fee required	Springer	https://link.springer.com/article/10.1007/s12160-011-9280-2
	subscription/membership/fee required	Silverchair Information Systems	https://academic.oup.com/abm/article-lookup/doi/10.1007/s12160-011-9280-2