Institution: | Research Economist, RTI International, RTP, North Carolina 27709-2194 (phone: 919-541-7023;fax: 919-541-6683;e-mail: ).;William Neal Reynolds Distinguished Professor, Department of Agricultural and Resource Economics, North Carolina State University, Raleigh, North Carolina 27695-8109 (phone: 919-515-4673;fax: 919-515-6268;e-mail: ). |