Dina Elkind, Zalevsky, Zeev , Levy, Uriel , and Mendlovic, David . 2003. “Optical Transfer Function Shaping And Depth Of Focus By Using A Phase Only Filter”. Applied Optics, 42, 11, Pp. 1925-1931. https://www.osapublishing.org/ao/abstract.cfm?uri=ao-42-11-1925.