Minneapolis. Public Library. Environmental Conservation Library. (1974). ECOL book catalog: Environmental conservation library. American Library Association.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रMinneapolis. Public Library. Environmental Conservation Library. ECOL Book Catalog: Environmental Conservation Library. Chicago: American Library Association, 1974.
एमएलए (9वां संस्करण) प्रशस्ति पत्रMinneapolis. Public Library. Environmental Conservation Library. ECOL Book Catalog: Environmental Conservation Library. American Library Association, 1974.
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