Is HCG 31 undergoing a merger or a fly-by interaction? M. G. Richer, L. Georgiev, M. Rosado, A. Bullejos, M. Valdez-Gutiérrez and D. Dultzin-Hacyan A&A, 397 1 (2003) 99-107 Published online: 11 December 2002 DOI: 10.1051/0004-6361:20021394