1. R. H. Snow, Powder Technol., 5: 351–364 (1972).
2. H. Rumpf, F. Faulhaber, K. Schönert, and H. Umhauer, Paper A3, Second European Symposium on Size Reduction, Dechema Monograph, 57 (1967).
3. K. Steier and K. Schönert, Third European Symposium on Size Reduction, Dechema Monograph, 69 (1972).
4. S. K. Ahuja, Powder Technol., 1 (1977).
5. R. E. Wellman and R. G. Crystal, U.S. Patent No. 378899Y (1974).