1. Elliott, R.S.: ‘The theory of antenna arrays’, Hansen, R.C., Microwave scanning antennas, (Academic Press 1966),2, Chap. 1,
2. Benjamin, R.: Modulation, resolution and signal processing in radar, sonar and related systems, (Pergamon Press 1966)
3. Gething, P.J.D.: Radio direction finding, (Peter Peregrinus, Stevenage 1978)