Bureau of Air Commerce (U.S. Department of Commerce) preliminary report into the crash of TWA Flight 6 on 6 May 1935.
Civil Aeronautics Bureau
1935-05-08
National Transportation Library, U.S. Department of Transportation. <a rel="nofollow" class="external free" href="https://rosap.ntl.bts.gov">https://rosap.ntl.bts.gov</a>