244 LOWDER, BECK, AND CONDON REFERENCES 1, H. L. Beck, W. J. Condon, and W. M. Lowder, Environmental Radiation Mea~ surements in the Southeastern, Central, and Western United States, 19621963, USAEC Report HASL-145, Health and Safety Laboratory, April 1964, 2, W. J. Condon, W, M. Lowder, and H, L. Beck, A Study of Population Expo~ sure to Environmental Radiation in Northern New England, Health and Safety Laboratory, to be published. 3, W, M. Lowder, H. L. Beck, W. J. Condon, and A. Shambon, Environmental Radiation Survey in Selected Communities of New York State, Health and Safety Laboratory, to be published. 4, W. M. Lowder, A. Segall, and W, J. Condon, Environmental Radiation Survey in Northern New England, in The Natural Radiation Environment.J, A. S. Adams and W. M, Lowder (Eds.), Chap, 56, pp. 907-918, University of Chi- cago Press, Chicago, 1964, 5, W. M, Lowder, W. J. Condon, and H, L. Beck, Field Spectrometric Investigations of Environmental Radiation in the USA, in The Natural Radiation Environment, J. A. 8S, Adams and W, M, Lowder (Eds.), Chap. 35, pp. 597616, University of Chicago Press, Chicago, 1964. 6. W, M. Lowder, H. L. Beck, and W. J. Condon, Spectrometric Determination of Dose Rates from Natural and Fall-out Gamma-Radiation in the United States, 1962-63, Nature, 202: 745 (1964). 7. H. L, Beck, W. J. Condon, and W. M, Lowder, Spectrometric Techniques for Measuring Environmental Gamma Radiation, USAEC Report HASL-150, Health and Safety Laboratory, October 1964. 8. W. 6. Condon, W. M. Lowder, and H. L. Beck, Pressurized Ionization Chambers for Environmental Radiation Measurements, Health and Safety Labo- ratory, to be published, . 9. J. AS. Adams and G, E. Fryer, Portable yRay Spectrometer for Field Determination of Thorium, Uranium, and Potassium, in The Natural Radiation Environment, J. A. S. Adams and W. M, Lowder (Eds.), Chap. 34, pp. 577-596, University of Chicago Press, Chicago, 1964. 10. H. L. Beck, to be published.

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