Reference sources include materials like encyclopedias, dictionaries, directories, or almanacs. These sources are useful for gaining a greater general knowledge about a subject.
These are sources you use to look for a reference to specific information, these are not books you would read from beginning to end.
Reference sources contain entries/articles that contain information like important people, places, dates, themes, or issues that are related to a specific topic.
We have reference sources that are in print and others that can be found electronically online.