Physics Letters A
Physics Letters A > 2006 > 351 > 3 > 143-152
Physics Letters A > 2006 > 356 > 3 > 220-225
Physics Letters A > 2006 > 358 > 2 > 134-141
Physics Letters A > 2006 > 351 > 3 > 143-152
Physics Letters A > 2006 > 356 > 3 > 220-225
Physics Letters A > 2006 > 358 > 2 > 134-141