Christie, A. (2012). The secret adversary (Center Point large print edition.). Center Point Publishing.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रChristie, Agatha. The Secret Adversary. Center Point large print edition. Thorndike, Maine: Center Point Publishing, 2012.
एमएलए (8वां संस्करण) प्रशस्ति पत्रChristie, Agatha. The Secret Adversary. Center Point large print edition. Center Point Publishing, 2012.
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