Major Extratropical Cyclones of the Northwest United States: Historical Review, Climatology, and Synoptic Environment. Monthly Weather Review. 2010, 138
(Nothing) Solar poles to become quadrupolar in May 2012 (Hinode) HistoricalClimatology.com (页面存档备份,存于互联网档案馆), further links and resources, updated 2014
Meteorological Society. 2000. ISBN 978-1878220349. (原始内容存档于2015-05-18). Tornado Climatology. National Climatic Data Center. January 29, 2007 [April 26, 2007]. (原始内容存档于June