1. Lewin, L.: Theory of Waveguides. Newnes-Butterworths, London (1975).
2. Schwinger, Yu.: Inhomogeneities in waveguides (lecture notes). Zarubezhnaya Electronika 3, 3–106 (1970) [in Russian]
3. Usanov, D.A., Gorbatov, S.S., Orlov, V.E., Venig S.B.: Resonances in semi-infinite waveguide with diaphragm, concerned with exitation of the high type waves. Pis’ma v Zhurnal Tekhnicheskoi Fiziki 26 (18), 47–49 (2000)
4. Datta, A., Chakraborty, A., Das, B.N.: Analysis of a strip loaded resonant longitudinal slot in the broad wall of a rectangular waveguide. IEE Proceedings H (Microwaves, Antennas and Propagation) 140 (2), 135–140 (1993)
5. Shestopalov, V.P.: Riemann-Hilbert Metod in the Theory of Diffraction and of Propagation of Electromagnetic Waves. Izdatel’stvo Kharkovskogo Universiteta, Kharkov (1971) [in Russian]