by J. Allen Hynek

UFOs Merit Scientific Study, letter in "Science", 21 October 1966; republished verbatim in Symposium on Unidentified Flying Objects, U.S. House of Representatives, 27 July 1968.  [USGPO].  Pgs. 12-13.

The UFO Experience: A Scientific Inquiry.  1972.  [Re].
The Edge of Reality: A Progress Report on Unidentified Flying Objects.  1975.  [Re].  With Jacques Vallée.
Night Siege: The Hudson Valley UFO Sightings.  1987.  [Bal].  With Philip J. Imbrogno and Bob Pratt.