The following websites are Subject Directories. They list websites according to their Dewey Decimal System. If you have a book on your topic, look at the call number. Then go to one of the "catalogs" listed below to find sites with that same Dewey number.
| Net Sites By the Numbers | Dewey Decimal System | CyberDewey | BUBL LINK |
| MGPL Webrary | IPL Youth Division Dewey Decimal Collection | Dewpoint | Teaneck Middle Schools CyberLibrary |
| Library Without Walls |