Name	Info	Provider	Link
	free resource	HighWire	https://thorax.bmj.com/lookup/pmidlookup?view=long&pmid=8539664
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=8539664.ui
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/8539664/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/8539664