Name	Info	Provider	Link
	subscription/membership/fee required	HighWire	https://thorax.bmj.com/lookup/pmidlookup?view=long&pmid=21459856
Air Pollution	free resource	MedlinePlus Health Information	https://medlineplus.gov/airpollution.html
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=21459856.ui
Full text from	free resource	CORE	https://core.ac.uk/reader/131140694?utm_source=linkout
Cited by Patents in	free resource	The Lens - Patent Citations	https://www.lens.org/lens/search/patent/list?q=citation_id:21459856