Evidence for pion absorption on four nucleons B. Rzehorz, G. Backenstoss, M. Džemidžić, M. Furić, A. Hoffart, T. Petković, H. Ullrich, H. J. Weyer, D. Weiser and M. Wildi Europhys. Lett., 34 2 (1996) 103-108 Published online: 01 September 2002 DOI: 10.1209/epl/i1996-00423-y