Welch, S. (1979). Signalling in telecommunications networks. Peter Peregrinus, on behalf of the Institution of Electrical Engineers.

Welch, Samuel. Signalling in Telecommunications Networks. Stevenage: Peter Peregrinus, on behalf of the Institution of Electrical Engineers, 1979.

Welch, Samuel. Signalling in Telecommunications Networks. Peter Peregrinus, on behalf of the Institution of Electrical Engineers, 1979.