Deep near-infrared imaging of RDCS J1252.9–2927 at z = 1.237 - The colour-magnitude diagram C. Lidman, P. Rosati, R. Demarco, M. Nonino, V. Mainieri, S. A. Stanford and S. Toft A&A, 416 3 (2004) 829-837 Published online: 09 March 2004 DOI: 10.1051/0004-6361:20031615