Ida, Nathan: 'Appendix D: Earth's radius compensation for elevation angle calculation' (Telecommunications, 2017), 'Transceiver and System Design for Digital Communications, 5th Edition', Chap. appendixd, pp. 491-491, DOI: 10.1049/PBTE080E_appendixd
IET Digital Library, https://digital-library.theiet.org/;jsessionid=8mlpmgrnv25y.x-iet-live-01content/books/10.1049/pbte080e_appendixd