Physics Letters A
Physics Letters A > 2010 > 374 > 6 > 886-890
Physics Letters A > 2010 > 374 > 25 > 2510-2516
Physics Letters A > 2010 > 374 > 34 > 3567-3571
Physics Letters A > 2010 > 374 > 41 > 4260-4264
Physics Letters A > 2010 > 374 > 46 > 4718-4723