YOSHIHIRO MARUYAMA is Professor Emeritus at the University of Tsukuba, Japan. He has also held positions as Associate Professor at Kyoto University, Japan, Lecturer at Essex University, UK, and Assistant Professor at the University of Massachusetts, USA. Previous posts include work as Advisor at the International Institute of Applied Systems Analysis, and as Policy Advisor in the National Development Planning Agency in the Government of Indonesia. TADASHI SONODA is Associate Professor at Nagoya University, Japan. Previously published works include 'Effects of the Internal Rate of Wage on Output Supply', and 'A System Comparison Approach to Distinguish Two Non-Separable and Non-Nested Agricultural Household Models'.