Ida, Nathan: 'Appendix C: Elevation effects on azimuth error' (Telecommunications, 2017), 'Transceiver and System Design for Digital Communications, 5th Edition', Chap. appendixc, pp. 489-490, DOI: 10.1049/PBTE080E_appendixc IET Digital Library, https://digital-library.theiet.org/;jsessionid=1lrh2grcpit7r.x-iet-live-01content/books/10.1049/pbte080e_appendixc