1. Dept. of Agric. Economics, 308 Ag Hall; Oklahoma State Univ.; Stillwater OK 74032
2. Monsanto Co.; 800 N. Lindbergh Blvd. St Louis MO
3. Monsanto Co.; 6 Rue Bani Hillal, El Menzah V Tunis Tunisia
4. INERA; L'Institute de l'Environment et de Recherches Agricoles 01; BP: 3628 Bobo-Dioulasso 01 Bobo-Dioulasso Houet Burkina Faso