Affiliation: | 1.Department of Rural Economics, Universidade Federal de Vi?osa, Avenida Purdue, s/no, Campus Universitário, Vi?osa, MG, 36570-900, Brazil ;2.Department of Agricultural and Consumer Economics, University of Illinois at Urbana-Champaign, 408 Munford Hall, 1391 W. Gregory, Urbana, IL, 61801, USA ; |