The strong gravitational lens finding challenge R. B. Metcalf, M. Meneghetti, C. Avestruz, F. Bellagamba, C. R. Bom, E. Bertin, R. Cabanac, F. Courbin, A. Davies, E. Decencière et al. (27 more) A&A, 625 (2019) A119 Published online: 22 May 2019 DOI: 10.1051/0004-6361/201832797