Physics Letters A
Physics Letters A > 2010 > 374 > 4 > 507-515
Physics Letters A > 2010 > 374 > 7 > 911-916
Physics Letters A > 2010 > 374 > 15-16 > 1686-1689
Physics Letters A > 2010 > 374 > 34 > 3380-3383
Physics Letters A > 2010 > 374 > 41 > 4260-4264