1. Analytical Research and Development, MRL, Merck & Co., Inc., Rahway, New Jersey 07065, United States
2. Department of Chemistry, Gustavus Adolphus College, Saint Peter, Minnesota 56082, United States
3. Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
4. Advanced Chemistry Development, Inc., Toronto, Ontario M5C 1B5, Canada