| General Encyclopedias |
| Encyclopedia of Delay-Insensitive Systems |
| Encyclopedia Smithsonian |
| EncycloZine |
| Treasure Troves of Science |
| Wikipedia |
| World Book |
| Subject Encyclopedias |
| Art Cyclopedia |
| Bhagvad Go Mandal (Gujarati Encyclopedia) |
| Encyclopedia of British History, 1500-1950 |
| Encyclopedia of Psychology |
| Encyclopedia of the Orient |
| Encyclopedia Mythica |
| Encyclopedia Smithsonian |
| Guide to Philosophy on the Internet |
| Internet Encyclopedia of philosophy |
| Medical Encyclopedia |
| Stanford Encyclopedia of Philosophy |
| Symbols.com:encyclopedia of Western Signs &Ideograms |
| WebMD |
| Webopedia |
| Whatis?com |
| Archpedia: Architecture Encyclopedia |
| Encyclopedia Astronautica |
| Eric Weisstein’s World of Science |
| The Extrasolar Planets Encyclopaedia |
| HealthCentral |
| The Mathematical Atlas: A Gateway to Modern Mathematics |
| EOLSS (Encyclopedia of Life supportive system) |
