1. Beck, A.H.W.: Words and waves, (Wiedenfeld & Nicolson 1967)
2. Karbowiak, A.E.: Trunk waveguide communication, (Chapman & Hall 1965)
3. White, R.W.: ‘Millimetre waveguide system research in the British Post Office’, Trunk telecommunication by guided waves, (IEE Conf. Publ. 71 1970), p. 319–324