Four Legs" p. 103 (sidebar) Penguin-Random House South Africa Talbot, Daniel B. "Frequency Acquisition Techniques for Phase Locked Loops" p. 166 John Wiley & Sons Berg, Jerome S. (2008) "Listening on the Short Waves, 1945 to Today" p. 290 McFarland & Co, Inc Smith, James R. "Introduction to Geodesy: The History and Concepts of Modern Geodesy" p. 67 John Wiley & Sons External links Official website South African Military History Society: Wadley's Ionosonde Trevor Lloyd Wadley - Genius of the Tellurometer on WorldCat SA Innovations You Didn't Know About – The Tellurometer (by Tellumat, manufacturer of the tellurometer) An explanation of The Wadley Loop by Lennart Benschop 1920 births 1981 deaths South African people of British descent White South African people People from Durban University of Natal alumni South African electrical engineers South African inventors 20th-century inventors South African scientists