Name	Info	Provider	Link
	subscription/membership/fee required	HighWire	https://thorax.bmj.com/lookup/pmidlookup?view=long&pmid=33414240
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=33414240.ui
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/33414240/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/33414240
	free resource	scite Smart Citations	https://scite.ai/reports/33414240