Civil Aeronautics Board report into the incident involving Delta Airlines Flight 15 on 4 January 1941.
Civil Aeronautics Board, US Department of Commerce
1941-12-02
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+101)">[1]</a>