“Practicing What You Preach: Evaluating Access of Open Access Research” (2017)…
“To explore the effectiveness of the new OA [DOI-based] finding tools, the next step of the study used the Chrome extensions for Google Scholar, Lazy Scholar (LS), Unpaywall, and the Open Access Button (OAB) to look for green OA versions of paywalled articles. [At 160 articles] The study sample size was triple the amount of articles that Grandbois and Beheshti (2014) found in their study.”