David F.W. Yap, S.K. Tiong, Johnny Koh, D.P. Andito, K.C. Lim and W.K. Yeo
Journal of Applied Sciences 12 ( 14 ): 1465 - 1473 , 2012
Ayad Atiyah Abdulkafi, Tiong Sieh Kiong, Johnny Koh, David Chieng and Alvin Ting
Journal of Applied Sciences 12 ( 14 ): 1418 - 1431 , 2012