Tolong jelaskan mengenai Spesifikasi (U-2S) dari Lockheed U-2

Hobson, Chris. Vietnam Air Losses, USAF, USN, USMC, Fixed-Wing Aircraft Losses in Southeast Asia 1961 - 1973. North Branch, Minnesota: Specialty Press, 2001. ISBN 1-85780-115-6.

Miller, Jay. Lockheed Martin's Skunk Works: The Official History... (updated edition). Leicester, UK: Midland Publishing Ltd., 1995. ISBN 1-85780-037-0.

Pedlow, Gregory W. and Donald E. Welzenbach. The Central Intelligence Agency and Overhead Reconnaissance: The U-2 and OXCART Programs, 1954-1974. Washington, DC: CIA, 1992.

Polmar, Norman. Spyplane: The U-2 History Declassified. St Paul, Minnesota: Zenith Imprint, 2001. ISBN 0-7603-0957-4.

The World's Great Stealth and Reconnaissance Aircraft. New York: Smithmark, 1991. ISBN 0-8317-9558-1.