Lian, Renzun; Pan, Jin: 'Method for constructing the non-radiative characteristic modes of perfect electric conductors', Electronics Letters, 2018, 54, (5), p. 261-262, DOI: 10.1049/el.2017.3393
IET Digital Library, https://digital-library.theiet.org/;jsessionid=1qfjms8ifbejr.x-iet-live-01content/journals/10.1049/el.2017.3393