According to the document:
“The subject of unidentified flying objects is a popular phenomenon of the period from 1947, evoking widespread speculation, and producing a literature of great variety and scope. This body of literature and documentation is source material for readers seeking better understanding to this question, which has involved the U.S. Air Force as well as other official groups.
This is believed to be the most comprehensive bibliography published to date on the subject, and includes the extensive UFO collection of the Library of Congress, as well as related material useful in understanding the nature of the question.
The bibliography was produced by the Library’s Division of Science and Technology with support provided by the Air Force Office of Scientific Research, a unit of the Office of Aerospace Research, the research agency of the U.S. Air Force.
The bibliographer is Miss Lynn E. Catoe, who also collected the books, journal articles, pamphlets, conference proceedings, tapes, original manuscripts, and other material listed here, a total of more than 1,600 items.
This literature survey was requested by AFOSR to assist a scientific research project at the University of Colorado under the direction of Dr. Edward U. Condon on unidentified flying objects. The research began 1 November 1966, and has been carried out with support provided by AFOSR at the direction of the Secretary of the Air Force under contract F44620-67-C-0035. The preparation of the bibliography was accomplished under AFOSR orders 67-0002 and 68-0003.”
The following document was received from the Defense Technical Information Center (DTIC) via FOIA Case 2015-52.