1. H. Holst, Elektriciteten, 1906.
2. P.L. Jensen, Inventor of the Loudspeaker, Chr. Erichsen, 1948.
3. A. Larsen, Telegrafonen and the Wireless, ATV, 1949.
4. E.R. Klausen, Notes in letters from the spring of 1983.
5. M. Clark, H. Nielsen, H. Buhl, Transmitter and Receiver, ATV, 1998.