Before revision: May 1993, Volume: 140, Issue: 3, pages 224- 236, ISSN: 0960-7641 The inventor was Alan S. Fitzgerald of Wynnewood, Pennsylvania, U.S.A. Fitzgerald, A. S., "The Petoscope: A New Principle in Photoelectric Applications", Wireless Engineer, Iliffe Electrical Publications, 1937U.S.
After revision: ,May 1993, Volume: 140, Issue: 3, pages 224- 236, ISSN: 0960-7641 The inventor was Alan S. Fitzgerald of Wynnewood, Pennsylvania, U.S.A. Fitzgerald, A. S., "The Petoscope: A New Principle in Photoelectric Applications", Wireless Engineer, Iliffe Electrical Publications, 1937U.S.