Name Info Provider Link
subscription/membership/fee required HighWire https://www.bmj.com/lookup/pmidlookup?view=long&pmid=18614504
free resource PubMed Central https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/18614504/
free resource Europe PubMed Central https://europepmc.org/abstract/MED/18614504