1. Achilles, H., u. W. Nagel: Ärztl. Wschr. 1955, 1074.
2. Anderson, N. P.: Arch. of Dermat. 11, 10 (1945).
3. Anderson, J. A., V. Bolin, W. W. Sutow and W. Kitto: Arch. of Dermat. 59, 251 (1949).
4. Ashby, D. W., and Th. Lazar: Lancet 1951, 1091.
5. Baader, E.: Arch. f. Dermat. 149, 261 (1925).