Y.W. Loh, P.S. H`ng, S.H. Lee, W.C. Lum and C.K. Tan
Asian Journal of Applied Sciences 3 ( 5 ): 310 - 316 , 2010
P.S. H`ng, S.H. Lee, Y.W. Loh, W.C. Lum and B.H. Tan
Asian Journal of Scientific Research 4 ( 3 ): 264 - 270 , 2011