Campbell-Smith, D. (2011). Masters of the post: The authorized history of the Royal Mail. Allen Lane.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रCampbell-Smith, Duncan. Masters of the Post: The Authorized History of the Royal Mail. Allen Lane, 2011.
एमएलए (9वां संस्करण) प्रशस्ति पत्रCampbell-Smith, Duncan. Masters of the Post: The Authorized History of the Royal Mail. Allen Lane, 2011.
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