Yu, Alfred C.: 'A brief review of ultrasound imaging and video' (Healthcare Technologies, 2018), 'Handbook of Speckle Filtering and Tracking in Cardiovascular Ultrasound Imaging and Video', Chap. 1, pp. 3-24, DOI: 10.1049/PBHE013E_ch1
IET Digital Library, https://digital-library.theiet.org/;jsessionid=fgaipftr7eeh.x-iet-live-01content/books/10.1049/pbhe013e_ch1