Keyhoe, D. E. (1954). Flying saucers from outer space: By Donald E. Keyhoe (1st print.). Permabooks.
Chicago-Zitierstil (17. Ausg.)Keyhoe, Donald E. Flying Saucers from Outer Space: By Donald E. Keyhoe. 1st print. Garden City, NY: Permabooks, 1954.
MLA-Zitierstil (8. Ausg.)Keyhoe, Donald E. Flying Saucers from Outer Space: By Donald E. Keyhoe. 1st print. Permabooks, 1954.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.