doi:10.2307/2004316 (1966 paper) gets matched to https://arxiv.org/pdf/hep-th/0502233v1.pdf (2004 paper) through http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.263.7400 which apparently has a matching DOI: "oa repository (via OAI-PMH doi match)"
{ "updated": "2017-10-20T15:56:27.009012", "url": "https://arxiv.org/pdf/hep-th/0502233v1.pdf", "url_for_pdf": "https://arxiv.org/pdf/hep-th/0502233v1.pdf", "url_for_landing_page": "http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.263.7400", "evidence": "oa repository (via OAI-PMH doi match)", "license": null, "version": "submittedVersion", "host_type": "repository", "is_best": true, "pmh_id": "oai:CiteSeerX.psu:10.1.1.263.7400", "endpoint_id": "CiteSeerX.psu", "repository_institution": "CiteSeerX.psu", "oa_date": null }
https://en.wikipedia.org/w/index.php?title=User_talk:OAbot&diff=prev&oldid=1193800304