GeoRef This link opens in a new window GeoRef was produced by the American Geological Institute. The database covers worldwide literature in geology and earth sciences. GeoRef contains a vast amount of indexed information, including 2.8 million bibliographic records from more than 3,500 journals covering a wide spectrum of geoscience literature. Other records featured within the database include: indexed books, maps, government reports, conference papers, theses and dissertations. Subject areas covered include: crystallography, economic geology, environmental geology, engineering geology, geochemistry, geophysics, hydrogeology, hydrology, marine geology, mineralogy, oceanography, petrology and paleontology. Coverage 1785 to the present.