Unidentified aerial object photographed near Zwishbergen, Switzerland, on July 26, 1975 : a case analysis /
Utrecht, Wim van.
Veldt, Frits van der.
Antwerpen, Belgium : Caelestia,
c1994.
"A research and publication project for unidentified aerial phenomena."
Includes bibliographical references (p. 214).
Unidentified flying objects