- Kiley, Don. "The Tiltrotor. Aviation's square peg?". Flight Safety Information Journal. Special Edition, July 2003. Accessed on 26 October 2008.
- Ristine, Jeff. "Obituary: Robert G. Ferry; Air Force veteran was record-setting test pilot" U-T San Diego, Feb. 2, 2009. Accessed: April 9, 2014.
- Markman and Holder, 2000
- Maisel et al., 2000, p. 141.
- The Bell XV-15 was flown over Fort Rucker's Nap-of-the-Earth (NOE) flight course from 10–13 September 1984. (Maisel et al., 2000, p. 145.)
- Maisel et al. 2000, p. 17.
- "XV-3, world’s first tiltrotor aircraft returns to Texas A half century after being built in Fort Worth". Press release from Bell Helicopter. 22 January 2004. Accessed at helis.com on 26 October 2008.
- "BELL HELICOPTER TEXTRON XV-3". National Museum of the USAF. Accessed on 26 October 2008.
- www.nationalmuseum.af.mil
