@article {2002, title = {On the K+P problem for a three-level quantum system: optimality implies resonance}, journal = {J.Dynam. Control Systems 8 (2002),no.4, 547}, number = {SISSA;30/2002/M}, year = {2002}, publisher = {SISSA Library}, doi = {10.1023/A:1020767419671}, url = {http://hdl.handle.net/1963/1601}, author = {Ugo Boscain and Thomas Chambrion and Jean-Paul Gauthier} }