Tham khảo Billy Meier

Korff, Kal K. (1995). Spaceships of the Pleiades: The Billy Meier Story. Amherst, NY: Prometheus Books. ISBN 0-87975-959-3. LCCN 94046992. OCLC 31754990.
Moosbrugger, Guido (2004) [Originally published 2001]. And Still They Fly!: The Henoch Prophecies (ấn bản 2). Tulsa, OK: Steelmark. ISBN 0-9711523-1-4. OCLC 55207214.
Sheaffer, Robert (1998). UFO Sightings: The Evidence. Amherst, NY: Prometheus Books. ISBN 1-57392-213-7. LCCN 98006410. OCLC 38738821.
Stevens, Wendelle C. (1982). UFO-- Contact from the Pleiades: A Preliminary Investigation Report (ấn bản 1). Tucson, AZ: UFO Photo Archives. ISBN 0-9608558-2-3. OCLC 42991526.
Stevens, Wendelle C. (1989). UFO-- Contact from the Pleiades: A Supplementary Investigation Report (ấn bản 1). Tucson, AZ: W.C. Stevens. ISBN 0-9608668-5-X. OCLC 21400094.

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