Name	Info	Provider	Link
	free resource	HighWire	http://erj.ersjournals.com/cgi/pmidlookup?view=long&pmid=21148224
Cited by Patents in	free resource	The Lens - Patent Citations	https://www.lens.org/lens/search/patent/list?q=citation_id:21148224
	free resource	Spiral, Imperial College Digital Repository	http://hdl.handle.net/10044/1/21922