Newspaper clipping, "Head of Hindenburg inquiry is apt at getting facts," from the New York Sun, May 10, 1937. Reports on members of the inquiry board, including Harold E. Hartney, appointed to investigate the Hindenburg disaster.
Born-digital video recording of an oral history with Donald M. "Don" Ulmer and interviewer John Barth, recorded as part of The Museum of Flight Oral History Program, June 19, 2017.