1. Ludwig, A.C.: ‘Spherical wave theory’, Rudge, A.W., Milne, K., Olver, A.D., Knight, P., The handbook of antenna design, (Peter Peregrinus Ltd., London, UK 1986),1, p. 101–127 behalf of IEE
2. Wood, P.J.: Reflector antenna analysis and design, (Peter Peregrinus Ltd., London, UK 1980),behalf of IEE
3. Hansen, J.E.: Spherical near-field antenna measurements, (Peter Peregrinus Ltd., London, UK 1986),behalf of IEE