1. Skarstrom, C. W. U.S. Patent No.2 944 627, July 12, 1960 and 3 237 377, March 1, 1966
2. Sorption Studies on American Coals
3. Nature of the porosity in American coals
4. U.S. Patent No.1 181 209, Feb.11, 1970; CA, 71, 126671d; CA, 74, 89157e
5. Zeolite Molecular Sieves;Breck,1974