1. Adler, H. H., Kerr, P. F., Bray, E. E., Stevens, N. P., Hunt, J. M., Keller, W. D., and Pickett, E. E., Infra-red Spectra of Reference Clay Minerals, 146 (Amer. Petr. Inst. Project 49, 1950).
2. Keller, W. D., and Pickett, E. E., Amer. Mineralogist, 34, 855 (1949).
3. Keller, W. D., and Pickett, E. E., Amer. J. Sci., 248, 264 (1950).
4. Hunt, J. M., Wisherd, M. P., and Bonham, L. C., Anal. Chem., 22, 1478 (1950).
5. Launer, P. J., Amer. Mineralogist, 37, 764 (1952).