Grealy, M. D. (1991). Knock: Apparition Gable from 1879 to the present. Cashin Printing Services.
Chicago-viite (17. p.)Grealy, Msgr Dominic. Knock: Apparition Gable from 1879 to the Present. Cashin Printing Services, 1991.
MLA-viite (8. p.)Grealy, Msgr Dominic. Knock: Apparition Gable from 1879 to the Present. Cashin Printing Services, 1991.
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