1. Hutchinson. Medical Times and Gazette. 1883. I. p. 4.
2. Hutchinson. Illustrated Medical News. Oct. 20. 1888. p. 82.
3. Hutchinson. Archives of Surgery. Vol. IV. plate LXVI. 1893.
4. Weaver and Tunnicliffe. Journal of Infectious Diseases. Vol. V. Nr. 5. December 18. 1908. p. 569.
5. Bourgeois and Egger. Revue Hebdom. May 22, 1909. p. 611.