Alireza Bahiraie, Noor Akma bt Ibrahim and A.K.M. Azhar
American Journal of Applied Sciences 6 ( 9 ): 1748 - 1757 , 2009
Alireza Bahiraie, Noor Akma Ibrahim, A.K.M. Azhar and Ismail Bin Mohd
Journal of Mathematics and Statistics 5 ( 3 ): 226 - 233 , 2009