Aitken, J. Ross; Jiasheng Hong, : 'Millimetre wave SIW diplexer with relaxed fabrication tolerances' (Electromagnetic Waves, 2019), 'Advances in Planar Filters Design', Chap. 12, pp. 373-403, DOI: 10.1049/SBEW535E_ch12
IET Digital Library, https://digital-library.theiet.org/;jsessionid=1xuajy7i7ih9q.x-iet-live-01content/books/10.1049/sbew535e_ch12