1. Appenzeller.-Centralbl. f. Augenheilk., p. 139, 1896.
2. Grimsdale.-Trans. Ophthal. Soc. U.K., No. 19, p. 267, 1899.
3. de Schweinitz.-Ophthal. Rec., p. 339, Dec., 1897.
4. quoted by Gould. - Med;Ibid;Rec,1907
5. Dujardin.-Jl. des Scien. Med. de Lille, July, 1900.