Coupled-channel study with Coulomb wave packets for ionization of helium in heavy ion collisions I. F. Barna, N. Grün and W. Scheid Eur. Phys. J. D, 25 3 (2003) 239-246 Published online: 15 July 2003 DOI: 10.1140/epjd/e2003-00206-6