First case of strong gravitational lensing by a QSO: SDSS J0013+1523 at z = 0.120 F. Courbin, M. Tewes, S. G. Djorgovski, D. Sluse, A. Mahabal, F. Rérat and G. Meylan A&A, 516 (2010) L12 Published online: 16 July 2010 DOI: 10.1051/0004-6361/201014376