1. Beeler, Collins andHale: Amer. J. Roentgenol.60, 466 (1948).
2. Breganzato: Arch. ital. Otol.33, 354 (1922). Ref. Z. org. Chir.22, 221.
3. Chitty: Brit. J. Surg.26, 193 (1938). Ref.Z. org. Chir.91, 196.
4. Dalicho: Röntgenprax.15, 361 (1943).
5. Dallas-Monro: Edinburgh 1963. Zit. beiMinski (1895).