Name	Info	Provider	Link
	subscription/membership/fee required	HighWire	https://jech.bmj.com/lookup/pmidlookup?view=long&pmid=17568046
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=17568046.ui
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/17568046/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/17568046