Civil Aeronautics Board report into the incident involving Pan American Flight 517-518 on 16 August 1941.
Civil Aeronautics Board, US Department of Commerce
1941
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+111)">[1]</a>