Personal Website - possible source of preliminary research information. Evaluate the website: look for the author's credentials as an authority on the subject (such as academic rank, degrees held, etc.), the presence of a bibliography, and update information - Use a search engine, such as Hotbot:

• http://www.hotbot.com  Choose "Advanced Search"
  
  • Specify "exact phrase", "must contain", if applicable
  • Specify domain of websites retrieved from the search
    • .edu - educational site
    • .gov - government site
    • .com - commercial site
    • .org - organization site  

Technical Reports - preliminary results of applied research and development. Technical reports are usually produced by an employee of a government agency or a commercial firm and often contain information that never appears in any other form of publication. Often these reports are signed by the employee's superior, but seldom is there any form of external evaluation of the information they contain.

• Defense Technical Information Center - STI network - http://stinet.dtic.mil/
• Environmental Protection Agency - NEPIS - http://www.epa.gov/cincl/
• Department of Energy, Office of Science and Technical Info - http://www.osti.gov

Patents - The UNL Engineering Library is Nebraska's only Patent and Trademark Depository Library. Using its CASSIS search system, a patent that has been granted for an invention can be identified and printed. Patents themselves are a valuable source of a wealth of information that cannot be obtained anywhere else.

• Patent search engine on the web site of the United States Patent and Trademark Office (www.uspto.gov) - http://www.uspto.gov/patft/index.html.
• Some article indexes also index patent literature.

EPrints/Preprints - preliminary electronic images of articles prior to submission for publication

• Department of Energy preprint network - http://www.osti.gov/preprints/ppnbrowse.html
• European Organization for Nuclear Research preprint site - http://preprints.cern.ch/.
• Los Alamos National Laboratory preprint server - http://xxx.lanl.gov/.