Name	Info	Provider	Link
	free resource	Elsevier Science	https://linkinghub.elsevier.com/retrieve/pii/S0954-6111(19)30095-2
COPD	free resource	MedlinePlus Health Information	https://medlineplus.gov/copd.html
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/31047114/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/31047114
	subscription/membership/fee required	ClinicalKey	https://www.clinicalkey.com/content/playBy/pii?v=S0954-6111(19)30095-2