1. US Environmental Protection Agency National Interim Primary Drinking Water Regulations. 055-000-001570. Washington, D.C. 1976
2. National Primary Drinking Water Regulations; Radionuclides; Advanced Notice of Proposed Rulemaking;US Environmental Protection Agency;Fed. Reg.,1991
3. Occurrence of Radon, Radium, and Uranium in Groundwater;Longtin;Jour. AWWA,1988
4. Occurrence of Uranium in Drinking Water in the United States;Cothern;Health Physics,1983