While many science publishers put a paywall in front of scientific articles, it’s often the case that these articles have been published elsewhere in an open format. “More and more funders and universities are requiring authors to upload copies of their papers to [open] repositories. This has created a deep resource of legal open access papers…” And that’s what Unpaywall draws on. READ MORE: Discover “Unpaywall,” a New (and Legal) Browser Extension That Lets You Read Millions of Science Articles Normally Locked Up Behind Paywalls | Open Culture