Litterature
- Beck J. Ann. Otol., Rhin. Laryng. 1913; 22: 273
- Berg E. Hospitalstidende 1924; 67: 604
- Crowe S. J. Laryngoscope 1940; 50: 658
- Crowe S. J. Year Book Eye. Ear, Nose and Throat 1949; 498
- Guild S. R. Arch. otolaryng. 1950; 50: 60
- Hill F. T. Arch. oto-laryng. 1931; 14: 775
- Lundgren N. Acta otolaryng. 1949; 37: 50
- Meyer W. Hospitalstidende 1868; 11: 177