United States. Weather Bureau. Daily synoptic series, historical weather maps. U.S. Weather Bureau.
Chicago-referens (17:e uppl.)United States. Weather Bureau. Daily Synoptic Series, Historical Weather Maps. Washington, D.C.: U.S. Weather Bureau.
MLA-referens (8:e uppl.)United States. Weather Bureau. Daily Synoptic Series, Historical Weather Maps. U.S. Weather Bureau.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.