1. Albrecht, H.: Wien. klin. Wochenschr. 1908. S. 99.
2. Auerbach: Münch, med. Wochenschr. 1905. Nr. 10, S. 449.
3. Aschner: New York med. journ. and med. record. Vol. 117, Nr. 11, p. 679. 1923.
4. Barlow: London med. gazette. May 1848.
5. Barnard: Brit. med. journ. 1908. p. 371.