The Best Reference Sites Online

Whether you're looking for the average rainfall in the Amazon rainforest, researching Roman history, or just having fun learning to find information, you'll get some great help using this list of the best research and reference sites on the web.

There are two types of reference sites. The first consists of specialized websites maintained by subject experts, who provide detailed and specific responses to your questions. The second type is run by generalists (often reference librarians) who don't necessarily answer your question but point you to the best resources for conducting your search.

The type of resources you choose depends on your question. If you're interested in a complex or obscure topic—the history of the mullet, for example—your best bet is to ask an expert on that subject. If you're interested in a broader topic or want an overview of a subject, the generalists usually provide you with better results. There are hundreds, if not thousands, of experts in specific subjects that can answer your questions on the web.

To find an expert in a specific category, try the following search string at Google or any other search engine: expert+[subject] (substitute your keyword for [subject]).

One of your best sources of expert information is your local librarian. Librarians are trained to find answers to obscure questions, they're friendly, and best of all, you can talk with them face to face. Librarians often ask you questions that you might not have considered, leading to even better results. You can get help from librarians online, too.

The Library of Congress enables you to not only ask a librarian but search catalogs of libraries from all over the world. This is truly a huge resource that should be on your Top 10 of best research sites. Anything from Academica Sinica in Taiwan to Yale University in the U.S. is here and ready to be searched.

Another useful service is Reference Desk.org. This is an extremely useful site, and while the Reference Desk does not personally answer questions, you have an excellent chance of finding someone who will be using their searchable subject directory.

Answers.com is a free reference search service. Its results are particularly useful since Answers.com weeds out extraneous or superficial sites and gets its results straight from encyclopedias, dictionaries, and other reference tools.

NASA's Ask An Expert is NASA's source for space and science research help. Search the Archives to see if your question has already been answered, or use the drop-down menus to browse through missions, topics, etc.

USA.gov is probably the best place to start when looking for specific government information. Make sure you check the All Topics and Services collection to get an idea of what there is at this exhaustive resource.

Reference.com is extremely simple to use with a basic layout. Just type your question in the search field.

Refdesk.com bills itself as the internet's fact checker. Includes in-depth research links to breaking news, editorials, This Day in History, Word of the Day, Daily Pictures and other references that make this a fun site with a ton of information.

Encyclopedia.com. As stated on their site, Encyclopedia.com provides users with more than 100 trusted sources including encyclopedias, dictionaries, and thesauruses.

Encyclopedia Brittanica. One of the world's oldest encyclopedias online.

Purdue University Library Quick Reference is a site with tons of information that includes resources specific to Purdue University and surrounding areas in Indiana.

Educator's Reference Desk is probably the best reference site online for teachers. It includes thousands of informative links, lesson plans, and general reference information.

Physician Desk Reference. Look for detailed medical information here.

iTools.com is an excellent site that serves as a gateway for reference and research links.

Baseball-Reference.com. Everything you ever wanted to know about the sport of baseball.

LibrarySpot.com. An excellent site that has hundreds of reference and research sources indexed all in one site.

FOLDOC - Free Online Dictionary of Computing is a detailed computing dictionary.