Edwards 2007a. Edwards, Roger. Wedge Tornado // National Weather Service. National Oceanic and Atmospheric Administration, 2007a. Посетен на 2007-02-28. (на английски)
Edwards 2007b. Edwards, Roger. Rope Tornado // National Weather Service. National Oceanic and Atmospheric Administration, 2007b. Посетен на 2007-02-28. (на английски)
Edwards 2009. Edwards, Roger. Public Domain Tornado Images // National Weather Service. National Oceanic and Atmospheric Administration, 2009. Посетен на 2009-11-17. (на английски)