1. Spencer, D. W., Robertson, D. E., Turekian, K. K., and Folsom, T. R., J. geophys. Res., 75, 7688 (1970).
2. Folsom, T. R., Hansen, N., Parks, jun., G. J., and Weitz, jun., W. E., Jl. appl. Spectrosc. (in the press).
3. Feldman, C., and Rains, T. C., Anal. Chem., 36, 405 (1964).
4. Folsom, T. R., US Atomic Energy Comm. Health and Safety Lab. Quart. Rep., HASL-249, I-12 (1972).
5. Sreekumaran, C., Pillai, K. C., and Folsom, T. R., Geochim. cosmochim. Acta, 32, 1229 (1968).