NASA technical reports server
Searchable citations and abstracts (with some full text) to NASA and external-to-NASA aerospace information found in research reports, journal articles,
conference and meeting papers, technical videos, mission-related operational documents, and preliminary data.
Technical Report Information on the Web for All Engineers, Aerospace, Civil, Computer Science, Energy, and Nuclear.
U.S. Geological Survey Maps, Imagery, and Publications
The U.S. Geological Survey website is a rich resources of information. This website provides links to the Publications Warehouse, Maps and Data, and more.