Civil Aeronautics Board report into the crash of a Northwest Airlines flight on 14 December 1940
Civil Aeronautics Board, US Department of Commerce
1941-10-25
US Department of Transportation Special Collections <a rel="nofollow" class="external autonumber" href="http://specialcollection.dotlibrary.dot.gov/Document?db=DOT-AIRPLANEACCIDENTS&amp;query=(select+85)">[1]</a>