Marton, L. (1980). „Ferdinand Braun: Forgotten Forefather”. Ур.: Suesskind, Charles. Advances in electronics and electron physics. 50. Academic Press. стр. 252. ISBN978-0-12-014650-5. Архивирано из оригинала 2014-05-03. г. „occurs first in a pair of later papers by Zenneck (1899a,b)”
Marton, L. (1980). „Ferdinand Braun: Forgotten Forefather”. Ур.: Suesskind, Charles. Advances in electronics and electron physics. 50. Academic Press. стр. 252. ISBN978-0-12-014650-5. Архивирано из оригинала 2014-05-03. г. „occurs first in a pair of later papers by Zenneck (1899a,b)”