Geological Survey (U.S.) & Bergquist, W. E. (1981). Worldwide directory of national earth-science agencies and related international organizations: A listing of governmental earth-science agencies and selected major international organizations whose functions are similar to those of the U.S. Geological Survey. U.S. Geological Survey.
Chicago Style (17th ed.) CitationGeological Survey (U.S.) and Wenonah E. Bergquist. Worldwide Directory of National Earth-science Agencies and Related International Organizations: A Listing of Governmental Earth-science Agencies and Selected Major International Organizations Whose Functions Are Similar to Those of the U.S. Geological Survey. Reston, Va.: U.S. Geological Survey, 1981.
MLA (9th ed.) CitationGeological Survey (U.S.) and Wenonah E. Bergquist. Worldwide Directory of National Earth-science Agencies and Related International Organizations: A Listing of Governmental Earth-science Agencies and Selected Major International Organizations Whose Functions Are Similar to Those of the U.S. Geological Survey. U.S. Geological Survey, 1981.