1. Yavnel, A. A., Borovskii, I. V., Ilin, N. P., and Marchukova, I. D., Doklady Akademii Nauk. U.S.S.R., 123, 2, 256 (1958).
2. Agrell, S. O., and Long, J. V. P., Proc. Second Intern. Conf. X-ray Microscopy and Microanalysis., Stockholm, 391 (Elsevier, Amsterdam, 1959).
3. Austin, A. E., Richard, N. A., and Schwartz, C. M., Proc. Second Intern. Conf. X-ray Microscopy and Microanalysis, 401.
4. Feller-Kniepmeier, M., and Uhlig, H. H., Geochim. Cosmochim. Acta, 21, 257 (1961).
5. Reed, S. J. B., and Long, J. V. P., Proc. Third Intern. Symp. X-ray Microscopy and Microanalysis, Stanford, U.S.A. (In the press).