http://www.spc.noaa.gov/faq/tornado/index.html#climatology
http://www.srh.noaa.gov.oun/tornadodata/okc_tornado.php
http://www.noaa.gov/tornadoes.html
www.chaseday.com/tornadoes.htm-10-
http://www.nssl.noaa.gov/nwstornado/
http://www.tornadoproject.com/nyths/myths.htm#top
http://www.wunderground.com/tornadofaq.asp
http://www.loudoun.gov/general/tornado.htm
www.public.iastate.edu/~atmos/people/tornado_safety_rules.html
www.redcross.ca/print.asp?id=009529