@BOOK {EHUI:1991b, title = {Indices for measuring the sustainability and economic viability of farming systems: RCMP research monograph, No. 3}, author = {Ehui, S. K. and Spencer, D. }, series = {RCMP Research monograph, No. 3}, year = {1991}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, note = {28p.}, }