The PubMed Central International (PMCI) network is a collaborative effort between the PMCI repositories, publishers, and funding organisations that wish to preserve and provide free access to journal articles authored by the researchers they support. For many years, the PMCI network has consisted of three nodes, PMC USA, Europe PMC and PMC Canada.
A Tue, study studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: