1. W. L. Barrow, Transmission of electromagnetic waves in hollow tubes of metal, Proc. IRE, 24, Oct. 1298 (1936).
2. J. H. Vogelman, Microwave communications, Proc. IRE 50, 907–911 (1962).
3. W. E. Kock, Radar, Sonar and Holography, Academic Press, New York, 1973.
4. H. T. Friis, Microwave repeater research, Bell Syst. Tech. J. 27, 183–246 (1948 (in this composite report, this author’s section, “Antenna Research,” describes the lenses of Figure 3.7 and 10.3).
5. W. E. Kock, Sound Waves and Light Waves, Doubleday, Garden City, N.Y., 1965, p. 128.