@UNPUBLISHED {OKALI:1979, title = {An evaluation of the farmer's knowledge and use of hydromorphic toposequences in the western state of Nigeria: findings from seletected areas in the Oshun river basin}, author = {Okali, C. and Oben, T. and Ojo, A. and Lawson, T. L. }, year = {1979}, note = {Discussion paper, No. 4/79}, }