1. Wilhelm Fabry (Fabricius Hildanus), Observationum et curationum chirurgicarum centuria V, Frankfurt, 1672; Obs. 21, pp. 59–61.
2. W. A. McKeown, “Extraction of a piece of steel from the vitreous humour by the magnet: Recovery of almost perfect vision,” Brit. Med. J., 800–801, 1874(i).
3. Julius Hirschberg, Der Electromagnet in der Augenheilkunde, Leipzig, 1885.
4. Simeon Snell, The Electro-magnet and Its Employment in Ophthalmic Surgery, London, 1883.
5. Ibid., pp. 1–2, 15–16.