@BOOK {RHOADES:1992, title = {The art of the informal agricultural survey: IITA research guide, No. 36}, author = {Rhoades, R. E. }, series = {IITA research guide, No. 36}, year = {1992}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, note = {57p.}, }