1. Board of Education Committee: Report on children with defective hearing, London H. M. Stationery Office (1938) Quoted.
2. Crowe, S.U. (1944): Ann., Otol., etc., St. Louis 53, 227, 1944.
3. Glorig, A. & Wheeler, D. E. (1955): Historical record of the Wisconsin State Fair Hearing Survey, Noise Control 1: 18–25, 1955 Quoted in A. M. A. Archieves, Otol., etc., 67, 69–70, 1958.
4. Goldberg, H. R. (1956): Coates, Otolaryngology, 1, 7, pp-41, 1956.
5. Hienemann, W. (1955): Diseases of the ear, nose and throat in Children, Butterworth, 1955.