BR1202–0725: an extreme multiple merger at z = 4.7P. Salomé, M. Guélin, D. Downes, P. Cox, S. Guilloteau, A. Omont, R. Gavazzi and R. NeriA&A, 545 (2012) A57DOI: https://doi.org/10.1051/0004-6361/201219955