Columbia subject headings:
Harvard subject headings:
Curiosities and wonders
Extraterrestrial beings.
Human-alien encounters
Occultism
Parapsychology
Pseudoscience.
Unidentified flying objects
Princeton subject headings:
Curiosities and wonders.
Extraterrestrial beings.
Human-alien encounters.
Occultism.
Parapsychology.
Pseudoscience.
Unidentified flying objects.