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This article should be expanded to cover the use of guard tones for telephony applications, wireless, and non-telephone applications.

• Welch, Samuel (1979). Signalling in telecommunications networks. Peregrinus. pp. 194, 242 –&#32, 244. ISBN  0906048044.
• Bigelow, Stephen J.; Carr, Joseph J.; Winder, Steve (August 9, 2001). "Wireless Telephones". Understanding Telephone Electronics (4th ed.). Newnes. pp. 348, 350. ISBN  0750671750.
• Mc Comb, Gordon (1984). "Cordless phones". Popular Science. 224 (4). Bonnier Corporation: 138. ISSN  0161-7370. {{ cite journal}}: Unknown parameter |month= ignored ( help)

-- Tothwolf ( talk) 01:25, 28 March 2010 (UTC) reply