*! Telfair, D., and Luetzelachwab, J., Science, 188, 829 (1962).
*3 Walton, A., J. Geophys. Res., 68, 1485 (1963).
2 Lowder, W. M., Segall, A., and Condon, W. J., in The Natural Radiation
Environment, edit. by Adams, J. A. §., and Lowder, W. M. (Univ.
Chicago Press, 1964).
*“ Franke, T., Rajewsky, B., and Schraub, A., Atomprazis, 9, 219 (1963).
** Alexander, L. T.. Meyer, M., Allen, J, S., and Hardy, E. P., Health and
Safety Lab. Rep. HASL-142, 325 (1964).
a”
* Salter, L. P., Health and Safety Lab. Rep. HASL-140, 170 (1963).
7 Gustafson, P. F., Argonne Nat. Lab. Rep, ANI-6049, 53 (1059).
** Gustafson, P. F. (private communication).
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