References
- Tiffany , W. R. , Hanley , C. N. and Sutherland , L. C. 1954 . A simple mechanical adapter for variable sidetone delay . J. Speech Dis. , 19 : 504 – 6 .
- Towers , T. D. 1965 . Elements of Transistor Pulse Circuits London : Iliffe, and Princeton, New Jersey: Van Nostrand .