1. Texas AgriLife Research (Texas A&M Univ. System)P.O. Box 1658VernonTX76385
2. Purdue Univ.Dep. of Agronomy915 W. State St.West LafayetteIN47907
3. North Carolina State Univ.Dep. of Biological and Agricultural Engineering, 185 Weaver LabsRaleighNC27695