'Back Matter' (Telecommunications, 2019), 'Microstrip and Printed Antenna Design', 3rd ed., Chap. bm, pp. -, DOI: 10.1049/PBTE083E_bm
IET Digital Library, https://digital-library.theiet.org/;jsessionid=tpeipw3brl7h.x-iet-live-01content/books/10.1049/pbte083e_bm