Short Primer on U238 Radioactive Decay Radon Key Information Journal of Health Physics, Vol.55, No.6 (December), pp989-992, 1988. "System for Measurement of 222Rn at Low Levels in Natural Waters." United States Geological Survey: Radon in Earth, Air and Water. United States Geological Survey: Radon Publications. Earthquake Information from the United States Geological Survey. Earthquake Engineering Research Institute National Earthquake Information Service The Earthquake Strong Motion Database Table of the Isotopes Berkeley Labs Exploring the Table of Isotopes NIST - National Institute of Science and Technology National Science Foundation PSIgate - Physical Sciences Information Gateway Suggestions - E-mail: rlupton@atral.com