Summers, C. G. (1978). Go to the Cowlitz, Peter Crawford: A biography of a Northwest pioneer surveyor. Summers Books].
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रSummers, Camilla G. Go to the Cowlitz, Peter Crawford: A Biography of a Northwest Pioneer Surveyor. [Kelso, WA: Summers Books], 1978.
एमएलए (8वां संस्करण) प्रशस्ति पत्रSummers, Camilla G. Go to the Cowlitz, Peter Crawford: A Biography of a Northwest Pioneer Surveyor. Summers Books], 1978.
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