1. Food and Resource Economics Department; University of Florida; P.O. Box 110240 Gainesville FL 32611-0240 USA
2. College of Economics and Management, Jilin Agricultural University, China; Food and Resource Economics Department, University of Florida; P.O. Box 110240 Gainesville FL 32611-0240 USA
3. Business Management, Harbin Institute of Technology Shenzhen Graduate School, Harbin Institute of Technology, HIT Campus of Shenzhen University Town; 518055 Shenzhen China
4. China Agricultural University; P.O. Box 118, Qinghua Dong Lu 17 Hao, Haidian District 100083 Beijing China
5. Horticultural Sciences, University of Florida; Citrus Research and Education Center; 700 Experiment Station Rd. Lake Alfred FL 33850 USA