1. F. A. Peyton and A. G. Craig, in “Restorative Dental Materials”, 5th ed., Michigan P. 177 (1975).
2. E. W. Skinner and R. W. Phillips, in “Science of Dental Materials”, 8th ed., Saunders Co. London, P. 311 (1982).
3. K. D. Jorgensen, Int. Dent. J., 26 (1976) 369.
4. K. Asgar and A. Malhorla, J. A. D., 96 (1978) 444.
5. J. R. Abbott and O. F. Makinsen, J. Biomedical Materials Res., 13 (1979) 857.