1. Grim, R. E., J. Geology50, 225–275 (1942).
2. Grout, F., Trans. Amer. Ceram. Soc.14, 71 (1912).
3. Terzaghi, C., Techn. Eng. News9, 10,11,36 (1928).
4. Langmuir, I., J. Amer. chem. Soc.34, 1848–1906 (1917).
5. Hendricks, S. B. u.M. E. Jefferson, Amer. Mineralogist13, 863–875 (1933).