R.W. Mukhongo, M.A. Kavoo-Mwangi, M.E. Kahangi, E.M. Ateka, A.B. Were, J.R. Okalebo, M.E. Mutegi, K.E. Mwangi, T.T. Tepeni, K.S. Njuguini, J.M. Onguso, S.A. Okoth and J.M. Jefwa
International Journal of Soil Science 10 ( 2 ): 45 - 62 , 2015