and Missile Systems: Volume 1 Post-World War II Fighters 1945–1973. Washington, DC: Office of Air Force History, 1978. . O'Leary, Michael, ed. "Deep Penetration", America's Forgotten Wings, Volume 1, 1994. Pace, Steve. Lockheed Skunk Works. St. Paul, Minnesota: Motorbooks International, 1992. . Pace, Steve. X-Fighters: USAF Experimental and Prototype Fighters, XP-59 to YF-23. St. Paul, Minnesota: Motorbooks International, 1991. . Simone, William J. Lockheed XF-90 Penetration Fighter, Air Force Legends 222. Simi Valley, California, Steve Ginter, 2020. . External links USAF Museum: XF-90 Operation Tumbler-Snapper: Atomic Blast Testing F-090 Lockheed F-90 Twinjets Low-wing aircraft