REFERENCES
- Carrea, J.U. (1937), Rev. Ortodonica I 1
- Lysell, L (1955), Acta Odont. Scand. 13 supp. 18, 1–137
- Petersen, K.B. and Kogon, S.L. (1971) J. Can. Dent. Assoc. 37, 275–279.
- Silva, L. (1938) in Lysell, L. (1955) Acta Odont. Scand. 13 supp. 18, 17.
- United States Department of Health, Education and Welfare (1967) Series II, no. 27.