Cross phase modulation in a five–level atomic medium: semiclassical theory C. Ottaviani, S. Rebić, D. Vitali and P. Tombesi Eur. Phys. J. D, 40 2 (2006) 281-296 Published online: 12 July 2006 DOI: 10.1140/epjd/e2006-00164-5