'Basic Radiators and Feed Methods' (Electromagnetic Waves, 2009), 'Antennas: Fundamentals, design, measurement', Chap. 4, pp. 119-167, DOI: 10.1049/SBEW040E_ch4
IET Digital Library, https://digital-library.theiet.org/;jsessionid=56nqvo562iuvi.x-iet-live-01content/books/10.1049/sbew040e_ch4