1. K. Asgar, IADR Program and Abstract of Papers, no. 15 (1971).
2. D. B. Mahler, ibid no. 14 (1971).
3. D. B. K. Innes and W. V. Youdelis, J. Canad. Dent. Assoc. 29 (1963) 587.
4. D. B. Mahler, J. D. Adey and J. Van Eysden, J. Dent. Res. 54 (1975) 218.
5. T. Takatsu, M. Iwaku and T. Fusayama, ibid 54 (1977) 40.