C.W. Recha, C.A. Shisanya, G.L. Makokha and R.N. Kinuthia
Asian Journal of Applied Sciences 1 ( 2 ): 123 - 135 , 2008
C.A. Shisanya, M.O. Makokha, S.K. Kimani, M. Kalumuna and A. Tenge
Journal of Applied Sciences 7 ( 13 ): 1755 - 1761 , 2007