Roger Edwards; Fred Ostby (2009). "Timeline of SELS and SPC". Storm Prediction Center. National Oceanic and Atmospheric Administration. Retrieved February 2, 2010.
Greg Carbin; Roger Edwards; Greg Grosshans; David Imy; Mike Kay; Jay Liang; Joe Schaefer; Rich Thompson. "Storm Prediction Center Frequently Asked Questions (FAQ)". Storm Prediction Center. National Oceanic and Atmospheric Administration. Retrieved May 13, 2010.