1. Bartels: (1) Klin. Mbl. Augenheilk.65, 910 (1920).
2. : (2) Graefes Arch.146, 3 (1943).
3. Bethe: Pflügers Arch.244, 1 (1940).
4. Cords: Klin. Mbl. Augenheilk.77, 781 (1926).
5. Köllner u.Hoffmann: 43. Ber. Dtsch. Ophthalm. Ges., Jena 1922, S. 222.