1. Center for Advanced Studies in Weed Research (NAPD), Agronomy Department
2. Chemistry Department
3. Agricultural Research Service, Cropping Systems and Water Quality Research Unit, United States Department of Agriculture, Columbia, Missouri 65211
4. Agricultural Research Service, Crop Genetics and Production Research Unit, United States Department of Agriculture, Stoneville, Mississippi 38776
5. Agrinatura Consultancy, Alfredo Guedes Street, 1949, 13416-901, Piracicaba, São Paulo, Brazil