N. Ghorab, O. Ghorab and N.E. Debbache
Journal of Applied Sciences 7 ( 20 ): 3119 - 3122 , 2007
Olga Ghorab, N. Ghorab, Elena Sokolova and N.E. Debbache
Journal of Applied Sciences 7 ( 20 ): 3115 - 3118 , 2007