First case of strong gravitational lensing by a QSO: SDSS J0013+1523 at z = 0.120F. Courbin, M. Tewes, S. G. Djorgovski, D. Sluse, A. Mahabal, F. Rérat and G. MeylanA&A, 516 (2010) L12DOI: https://doi.org/10.1051/0004-6361/201014376
