'Digital transmission over flat fading' (Telecommunications, 2017), 'Introduction to Digital Wireless Communications', Chap. 4, pp. 55-90, DOI: 10.1049/PBTE072E_ch4
IET Digital Library, https://digital-library.theiet.org/;jsessionid=74g8hijdlet14.x-iet-live-01content/books/10.1049/pbte072e_ch4