1. E. W. Skinner andR. W. Phillips, “The Science of Dental Materials”, 6th Edn. (W. B. Saunders and Co, Philadelphia and London, 1967), p. 492.
2. F. A. Peyton, “Restorative Dental Materials” (C. V. Mosby, St Louis, 1964), p. 508.
3. B. Axelsson,Odont Revy 15 (1964) 150.
4. J. A. R. Genge, A. Holroyd, J. E. Salmon, andJ. G. L. Wall,Chem. Industr. (1955) 357.
5. J. E. Salmon andJ. G. L. Wall,J. Chem. Soc. (1958) 1128.