1. USEPA Nationwide Occurrence of Radon and Other Natural Radioactivity in Public Water Supplies 1985
2. Hess , C.T. The Occurrence of Radioactivity in Public Water Supplies in the United States. USEPA Natl. Workshop on Radioactivity in Drinking Water, Easton, Md. 1983
3. Rapid Measurements of Radon-222 Concentrations in Water With a Commercial Liquid Scintillation Counter.;Pritchard;Health Phys.,1977
4. Lowry , J.D. Personal communication 1986
5. USEPA Office of Drinking Water Personal communication 1988