Ewart, Phil. Trans. 179 (B), 1888, pp. 399, 410, and 539; 183 (B), 1893, p. 389.
Ballowitz, Arch. Mikr. Anat. l. 1897, p. 686; Carl Sachs, Untersuchungen am Zitteraal, Leipzig, 1881.
Ballowitz, Das Electrische Organ des Africanischen Zitterwelses, Jena, 1899.
Gotch, Phil. Trans. 178, 1888, p. 487.
Id. op. cit. p. 535.