1. National Agricultural Cooperative Federation (Nonghyup); Saemunangil 91; Chung-gu; Seoul; Korea
2. Department of Agricultural and Resource Economics; Oregon State University; Corvallis; OR; 97331; USA
3. U.S. Department of Agriculture; Economic Research Service; 1400 Independence Avenue SW, Mail Stop 1800; Washington; DC; 20250-0002; USA