A relativistic quark model for mesons with an instanton-induced interaction M. Koll, R. Ricken, D. Merten, B.C. Metsch and H.R. Petry Eur. Phys. J. A, 9 1 (2000) 73-94 Published online: 15 September 2000 DOI: 10.1007/PL00013675