Blake, Joseph A. (1979), „Ufology: The intellectual development and social context of the study of unidentified flying objects“, The Sociological Review (27): 315, doi:10.1111/j.1467-954x.1979.tb00067.x, ISSN1467-954X
Blake, Joseph A. (1979), „Ufology: The intellectual development and social context of the study of unidentified flying objects“, The Sociological Review (27): 315, doi:10.1111/j.1467-954x.1979.tb00067.x, ISSN1467-954X