Gregson, J. M. (2009). Darkness visible: A Lambert and Hook mystery (1st world ed.). Severn House.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रGregson, J. M. Darkness Visible: A Lambert and Hook Mystery. 1st world ed. Sutton: Severn House, 2009.
एमएलए (8वां संस्करण) प्रशस्ति पत्रGregson, J. M. Darkness Visible: A Lambert and Hook Mystery. 1st world ed. Severn House, 2009.
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