1. Perret, R., and Ruland, W., Paper SS-22, Ninth Carbon Conference, Boston, Mass., June 1969.
2. Rosenberg, A. J., J. Amer. Chem. Soc., 78, 2929 (1956).
3. Gregg, S. J., and Sing, K. S. W., Adsorption, Surface Area and Porosity, 86 (Academic Press, New York, 1967).
4. Goan, J. C., and Prosen, S. P., ASTM Symposium, San Francisco, June 1968.