Keyhoe, D. E. (1954). Flying saucers from outer space: By Donald E. Keyhoe (1st print.). Permabooks.
Cita Chicago (17th ed.)Keyhoe, Donald E. Flying Saucers from Outer Space: By Donald E. Keyhoe. 1st print. Garden City, NY: Permabooks, 1954.
Cita MLA (8th ed.)Keyhoe, Donald E. Flying Saucers from Outer Space: By Donald E. Keyhoe. 1st print. Permabooks, 1954.
Atenció: Aquestes cites poden no estar 100% correctes.