1. Galwey, A. K., Nature, 223, 1257 (1969).
2. Galwey, A. K., Chem. Commun., 577 (1969).
3. Shimoyama, A., and Johns, W. D., Nature phys. Sci., 232, 140 (1971).
4. Johns, W. D., and Shimoyama, A., Bull. Am. Assoc. Petrol. Geol., 56, 2160 (1972).
5. Fripiat, J. J., Trans. 9th Congr. Int. Soil Sci. Soc. (Adelaide), 1, 679 (1968).