1. Antenna standards committee of the IEEE Antennas and Propagation group. IEEE Standard Definitions of Terms for Antennas, pp. 145–1973. IEEE Std.
2. Kraus, J.D.: Antennas. McGraw-Hill, New York (1950, 1988, 2001)
3. Tai, C.-T., Pereira, C.: An approximate formula for calculating the directivity of an antenna. IEEE Trans. Antennas Propag. 24(2), 235–236 (1976)
4. Balanis, C.A.: Antenna Theory—Analysis and Design, 3rd edn. Wiley, Hoboken/NJ (2005)
5. Friis, H.T.: A note on a simple transmission formula. Proc. IRE. 34, 254-256 (1946)