Applied Earth Sciences, Inc., 7322 Southwest Freeway, Suite 1000, Houston, Texas 77074, USA, US
G. C. Barbee
Soil and Crop Sciences Department, Texas A&M University, College Station, Texas 77843, USA, US
K. W. Brown & J. C. Thomas
Veterinary Anatomy and Public Health Department, College of Veterinary Medicine, Texas A&M University, College Station, Texas 77843, USA, US
K. C. Donnelly
Agency for Toxic Substances and Disease Registry, Division of Toxicology, MS-E29, 1600 Clifton Road, Atlanta, Georgia 30333, USA, US
H. E. Murray