United States. Forest Service. (1989). Northern Region: Summer of '88. Forest Service, US Dept. of Agriculture.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रUnited States. Forest Service. Northern Region: Summer of '88. [Missoula, Mont.?]: Forest Service, US Dept. of Agriculture, 1989.
एमएलए (8वां संस्करण) प्रशस्ति पत्रUnited States. Forest Service. Northern Region: Summer of '88. Forest Service, US Dept. of Agriculture, 1989.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.