1. Yates A. L.: The Principles and Practice of Otology (with Watkyn-Thomas F. W.), London, H. K. Lewis and Co., Ltd., 1932, p. 77.
2. Krieg W. J. S.: Functional Neuroanatomy, Philadelphia, The Blakiston Company, 1942, p. 153.
3. Politzer A.: Disease of the Ear, 4th ed., Philadelphia, Lea Brothers & Co., 1902, p. 307.