Name	Info	Provider	Link
	free resource	Primary Care Respiratory Society UK	https://doi.org/10.4104/pcrj.2013.00019
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/23426420/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/23426420
	free resource	scite Smart Citations	https://scite.ai/reports/23426420