Gold represents those publications where the final published version of an article (Version of Record) is freely and permanently available online immediately on publication for anyone, anywhere to read. This includes articles in hybrid journals. See Methodology and Notes for more information.
Green represents those publications where a version of an article is publicly shared online, often as an Accepted Manuscript. To support a sustainable business model, publishers may maintain an embargo and/or may retain an Exclusive License to Publish. Articles, reviews and conference papers are counted as Green open access only if they are not also Gold. See Methodology and Notes for more information.
Bronze represents those publications that are made free-to-read on the publisher’s website, but are not identified as gold for one of the following reasons: access for a limited duration, an unclear license, or a license that is clear but is not a Creative Commons license. See Methodology and Notes for more information.
Subscription-only represents those publications that are available through individual or institutional subscriptions, individual purchases, or other programs (e.g. Research4Life) but not available through Open Access. See Methodology and Notes for more information.