1. Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV 89193-9954, USA
2. Present address: Battelle, 397 Washington Street, Duxbury, MA 02332, USA
3. Louisville Water Company, 550 South Third St., Louisville, KY 40202, USA
4. Present address: Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, P.O. Box 210011, Tucson, AZ 85721, USA
5. Public Works Department, 2330 McCulloch Blvd. N., Lake Havasu City, AZ 86403, USA