'Introduction to Sensing' (Radar, Sonar and Navigation, 2009), 'Introduction to Sensors for Ranging and Imaging', Chap. 1, pp. 1-22, DOI: 10.1049/SBRA014E_ch1
IET Digital Library, https://digital-library.theiet.org/;jsessionid=1sas51dyu7mpz.x-iet-live-01content/books/10.1049/sbra014e_ch1