The mass profile of early-type galaxies in overdense environments: the case of the double source-plane gravitational lens SL2SJ02176-0513H. Tu, R. Gavazzi, M. Limousin, R. Cabanac, P. J. Marshall, B. Fort, T. Treu, R. Péllo, E. Jullo, J.-P. Kneib and J.-F. SygnetA&A, 501 2 (2009) 475-484DOI: https://doi.org/10.1051/0004-6361/200911963