(
a) Distribution of papers based on license category. Licenses were divided as: CC0, CC-BY, PD, CC-BY-SA, Implied OA, CC-BY-NC, CC-BY-NC-SA, CC-BY-ND, CC-BY-NC-ND, and those without any particular license. (
b) Distribution of papers with OA license (CC0, CC-BY, PD and CC-BY-SA), restricted license (Implied OA, CC-BY-NC, CC-BY-NC-ND, CC-BY-NC-SA, CC-BY-ND and ACS Specific) or without a license of each OA typology. (
c) License type (open, restricted or absent) attending each manuscript location: repository or non-repository (journal page, DOAJ or PDF). (
d) Number of papers present in PubMed Central (PMC), other repositories or at both locations, together with the number of these lacking any license. (Data extracted from PubMed: 23
rd April 2020).