Collins effect and single spin azimuthal asymmetriesin the HERMES and COMPASS experiments A. V. Efremov, K. Goeke and P. Schweitzer Eur. Phys. J. C, 32 3 (2004) 337-346 Published online: 26 November 2003 DOI: 10.1140/epjc/s2003-01398-6