1. University of Pennsylvania, School of Veterinary Medicine; Department of Clinical Studies; New Bolton Center Campus Kennett Square PA 19348 USA
2. PA Equine Toxicology and Research Center, Department of Chemistry; West Chester University; 220 East Rosedale Avenue West Chester PA 19382 USA
3. Sigma-Aldrich Corp, Pharmaceutical and Bioanalytical Research; 595 North Harrison Rd. Bellefonte PA 16823 USA
4. New York Drug Testing and Research Program; Morrisville University; 777 Warren Road Ithaca NY 14850 USA