Bohlen, S. R. (1998). Geology for a changing world: A science strategy for the Geologic Division of the U.S. Geological Survey, 2000-2010. U.S. G.P.O. Free on application to U.S. Geological Survey, Information Services.
Lua i Stíl Chicago (17ú heag.)Bohlen, Steven R. Geology for a Changing World: A Science Strategy for the Geologic Division of the U.S. Geological Survey, 2000-2010. Washington, Denver, CO: U.S. G.P.O. Free on application to U.S. Geological Survey, Information Services, 1998.
Lua MLA (9ú heag.)Bohlen, Steven R. Geology for a Changing World: A Science Strategy for the Geologic Division of the U.S. Geological Survey, 2000-2010. U.S. G.P.O. Free on application to U.S. Geological Survey, Information Services, 1998.
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