1. Bucky: Münch. med. Wschr.1913, 186.
2. Hertel: Graefes Arch.69, 126 (1909).
3. Hoeve, V. d.: Graefes Arch.82, 58 (1912).
4. Nugent: Arch. physic. Ther. (Am.)21, 297 (1940). Ref. Zbl. Ophthalm.46, 376 (1941).
5. Rajewsky: Dtsch. med. Wschr.1937, 780, 1065, 1221.