Ross, John c. What were the doughnuts? Fate, Spring 1948: 12-14.
In an analysis of military aircraft and weaponry, author states it would be dif-
ficult to confuse them with the flying disks reportedJy seen by Kenneth Arnold.
He suggests extraterrestrial origin.
Ruppelt, Edward J. Inside stor1 of the saucers. Sci~nce digest, v. 39, Apr. 1956.
35-41.
Condensed from a chapter of the book, The Report on Unidentified Flying Objects,
published in New York by Doubleday, 1956. Author describes his activities as
head of·_:, AF's Project Blue Book, 1951-1953. He states that while balloons,
alrplan~i;, stars, and many other C'lmmon objects have been reported as UFOs,
there are hundreds of other UFO reports which carry the verdict, "Conclusion
Unknown."
----- What our Air Force found out about flying saucers. True, May 1954: 19-20,
22, 24, 26, 30, 124-134.
Ruppelt, in charge of USAF's Project IDue Book f::-om 1951 to 1953, reports
w!lat he learned about flying saucers during this period. He states his opinion
that the saucers are either inter planetary or do not exist.
Sagan, Carl. Unidentified flyL;g object. h. Encyclopedia Americana, v. 27, New
York, Americana Corp., 1967. p. 368-369.
"Unidentified flying ol>ject" is defined and then discussed in terins of investiga-
tions, hypotheses of extraterrestrial origin, and psychological factors.
Salisbury, Frank B. The scientist and the UFO. Bioscience, Jan. 1967: 15-24.
Five hypothc·ses purporting to explain the UFO phenomenon are discussed and
a few representative sightings considered.
Sharp, Peter F. An appraisal of the present UFO position. Flying saucer revi.:'w,
v. 7, 1961: 19-22.
Analysis of current hypotheses which attempt tr, explain UFO phenomena.
Simons, Rodger L. The space snip hokum. The Catholic wo-rld, v. 140, Nov. 1934:
164-170.
Arguments on the improbability of there ever being travel to and from other
planets.
Situation report: What is the unidentified flying object situation these days? Ameri-
can engineer, Mar. 1967: 55.
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