1. American Dental Association, Guide to Dental Materials and Devices, 7th ed., 1974–75, Chicago, Ill., 1974
2. Anon, U. S. Dept. H. E. W., Pub. N.I.H., 77–1198 (1976)
3. Anon, Proofs, (April 13–16, 1977 )
4. D. A. Atwood, J. Prosth. Dent. 20, 101 (1968)
5. L. J. Boucher, et al., J. Prosth. Dent., 19, 581 (1968)