Reference
- Beasley W. C. The general problem of deafness in the population. Laryngoscope 1940; 9: 856
- Bentzen O., Jelnes K. Incidence of impaired hearing in Denmark. Acta Otolaryng. (Stockh.) 1955; 45: 3
- Wilkins I. T. The prevalence of deafness in England, Scotland and Wales. Acta Otolaryng. (Stockh.) 1950, Suppl. 90