1. Department of Economics, Kangwon National University, Chuncheon-si, Gangwon-Do, Korea.
2. Department of Health Policy and Management, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
3. Department of Agricultural Economics, Texas A&M University, College Station, TX, USA.
4. Food and Resource Economics Department, University of Florida, Gainesville, FL, USA.
5. Arkansas Center for Health Improvement, Little Rock, AR, USA; Department of Health Policy and Management, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA.