@BOOK {CARSKY:1992a, title = {Effect of toposequence position on performance of rice varieties in inland valleys of West Africa: RCMP Research monograph, No. 9}, author = {Carsky, R. and Masajo, T. M. }, series = {RCMP Research monograph, No. 9}, year = {1992}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, }