Articles
Inexplicata, The Journal of Hispanic Ufology : 09-15-2004 - Brazil: Strange Photos from Uberaba (humanoid skull twice the size of adult human skull)
The Pitch.com: Space Case - Short Bio of Mac Tonnies, author of After the Martian Apocalypse and The Cydonian Imperative website
Earthfiles: 11-11-2004 - Strange Metal Pieces from Plains of San Agustin Alleged UFO Crash Site Analyzed

Books
Col. Philip J. Corso, U.S. Army, ret.:
The Day After Roswell: A Former Pentagon Official Reveals the U.S. Government's Shocking UFO Cover-Up
Lutz Gentes, psychologist:
Die Wirklichkeit der Goetter - Raumfahrt im fruehen Indien (The Reality of the Gods Space Travel in Ancient India)
Steven Greer, M.D., director of 'The Disclosure Project':
Disclosure: Military and Government Witnesses Reveal the Greatest Secrets in Modern History
Extraterrestrial Contact: The Evidence and Implications
David M. Jacobs, Ph.D., Assoiate Professor of Temple University:
Secret Life: Firsthand, Documented Accounts of UFO Abductions
Mac Tonnies, science fiction writer, critic, columnist, maintains the Cydonian Imperative, a popular website devoted to extraterrestrial archaeology:
After the Martian Apocalypse: Extraterrestrial Artifacts and the Case for Mars Exploration
Graham Hancock, journalist:
The Mars Mystery: The Secret Connection Between Earth and the Red Planet

Websites
CUFOS (J. Allen Hynek Center For UFO Studies), Chicago, IL
David Seereda's Evidence - The Case for NASA UFOs, Los Angeles, CA
Filer's Files (National UFO Center)
HBCC UFO Research
Independent Researchers' Association for Anomalous Phenomena (IRAAP), Albany, NY
Mutual UFO Network (MUFON), Morrison, CO
National UFO Reporting Center (NUFORC), Seattle, WA
Northwest Saskatchewan UFO Research Center, Province of Saskatchewan, Canada
Mac Tonnies' The Cydonian Imperative 1 - An Independent Effort to Assess Possible Extraterrestrial Artifacts on Mars
Mac Tonnies' The Cydonian Imperative 2 (Blogspot)
Richard C. Hoagland's The Enterprise Mission, Albuquerque, NM
Richard M. Dolan's Through the Keyhole - Dolan holds an MA in History from the University of Rochester, a BA in History from Alfred University, a Certificate in Political Theory from Oxford University, was a Rhodes Scholar finalist; prior to his interest in anomalous phenomena, Dolan studied US Cold War strategy, Soviet history, international diplomacy.