1. Singer, W.: Verh. Dtsch. Zool. Ges. 1985
2. Nieuwkoop, P.D.: Normal Table of Xenopus laevis (Daudin). Amsterdam: North-Holland 1967
3. Neubert, J.: Aviat. Space Environ. Med. 50, 10, 1058 (1979)
4. Vinnikov, Ya. A., et al.: Acta Otolaryngol. 87, 90 (1978)
5. Ross, M.D., et al.: Physiologist 28, Suppl, S-217 (1985)