1. Office of Science, Center for Tobacco Products, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Document Control Center, Building 71, Room G335, Silver Spring, Maryland 20993, United States
2. U.S. Food and Drug Administration, Center for Veterinary Medicine, Office of Applied Science, Division of Residue Chemistry, 8401 Muirkirk Road, Laurel, Maryland 20708, United States
3. Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, Georgia 30341, United States