Physics Letters A
Physics Letters A > 1999 > 251 > 4 > 279-285
Physics Letters A > 1999 > 251 > 4 > 250-258
Physics Letters A > 1999 > 251 > 4 > 273-278
Physics Letters A > 1999 > 251 > 4 > 223-228
Physics Letters A > 1999 > 251 > 4 > 259-261
Physics Letters A > 1999 > 251 > 4 > 236-240
Physics Letters A > 1999 > 251 > 4 > 286-287
Physics Letters A > 1999 > 251 > 4 > 247-249
Physics Letters A > 1999 > 251 > 4 > 262-268
Physics Letters A > 1999 > 251 > 4 > 269-272
Physics Letters A > 1999 > 251 > 4 > 229-235
Physics Letters A > 1999 > 251 > 4 > 241-246