Kingsbury, D. (2002). Psychohistorical crisis (First mass market edition.). Tom Doherty Associates Book.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रKingsbury, Donald. Psychohistorical Crisis. First mass market edition. New York: Tom Doherty Associates Book, 2002.
एमएलए (9वां संस्करण) प्रशस्ति पत्रKingsbury, Donald. Psychohistorical Crisis. First mass market edition. Tom Doherty Associates Book, 2002.
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