| 1 | Encyclopedia | https://www.encyclopedia.com/ |
| 2 | Internet Archive | https://archive.org/details/the-world-book-encyclopedia |
| 3 | Info Please | https://www.infoplease.com/ |
| 4 | Britannica | https://www.britannica.com/ |
| 5 | The Free Dictionary | https://www.thefreedictionary.com/ |
| 6 | World History Encylopedia | https://www.worldhistory.org/ |
| 7 | Almanac | https://www.almanac.com/ |
| 8 | Thesaurus | https://www.thesaurus.com/ |
| 9 | Oxford Research Encyclopedias | https://oxfordre.com/ |
| 10 | Macmillan Dictionary | https://www.macmillandictionary.com/ |
| 11 | Collins | https://www.collinsdictionary.com/ |
