| Bartleby.com - http://www.bartleby.com/ Includes the Columbia Encyclopedia, Sixth Edition, dictionaries, and thesauri. - Read more |
| World Book, Inc. - http://www.worldbook.com/wb/Home Official site promoting its excellence in the production of award-winning encyclopedias, reference sources, and multimedia projects for the home and schools. - Read more |
| Wikipedia - http://en.wikipedia.org/wiki/Main_Page Free open-source multilingual encyclopedia. - Read more |
