Physics Letters A
Physics Letters A > 2006 > 353 > 1 > 76-81
Physics Letters A > 2006 > 353 > 5 > 383-388
Physics Letters A > 2006 > 355 > 6 > 460-464
Physics Letters A > 2006 > 353 > 1 > 76-81
Physics Letters A > 2006 > 353 > 5 > 383-388
Physics Letters A > 2006 > 355 > 6 > 460-464