Sachidananda, M.; Ramakrishna, S.: 'Optimum aperture distributions in the presence of blockage', Electronics Letters, 1978, 14, (17), p. 556-558, DOI: 10.1049/el:19780377
IET Digital Library, https://digital-library.theiet.org/;jsessionid=1f3yfvv1jmixx.x-iet-live-01content/journals/10.1049/el_19780377