Ramos-Llorden, Gabriel; Aja-Fernandez, Santiago; Vegas-Sanchez-Ferrero, Gonzalo: 'Introduction to speckle filtering' (Healthcare Technologies, 2018), 'Handbook of Speckle Filtering and Tracking in Cardiovascular Ultrasound Imaging and Video', Chap. 5, pp. 81-93, DOI: 10.1049/PBHE013E_ch5
IET Digital Library, https://digital-library.theiet.org/;jsessionid=2f67056glxntj.x-iet-live-01content/books/10.1049/pbhe013e_ch5