Name	Info	Provider	Link
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=20553134.ui
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/20553134/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/20553134
	subscription/membership/fee required	Silverchair Information Systems	https://meridian.allenpress.com/anesthesia-progress/article-lookup/doi/10.2344/0003-3006-57.2.45