A quadruply imaged quasar with an optical Einstein ring candidate: 1RXS J113155.4–123155D. Sluse, J. Surdej, J.-F. Claeskens, D. Hutsemékers, C. Jean, F. Courbin, T. Nakos, M. Billeres and S. V. KhmilA&A, 406 2 (2003) L43-L46DOI: https://doi.org/10.1051/0004-6361:20030904
