by Gitau, A.N., Gumbe, L.O., Biamah, E.K.
Published in Soil & tillage research (01.09.2006)

by E. B. K. Mutai, P. O. Otieno, A. N. Gitau, D. O. Mbuge, D. A. Mutuli
Published in Research Journal of Applied Sciences, Engineering and Technology (25.07.2011)

by Luvai, A K, Gitau, A N, Njoroge, B N K, Obiero, J P O
Published in International journal of engineering innovations and research (01.05.2014)