Sources of information are often considered primary, secondary, or tertiary depending on their originality and their proximity to when the information was created. Consider if it is an original work, or whether it evaluates or comments on the works of others. Also consider the proximity, or how close the information is to a first-hand account or if it is after the fact.
It can be difficult to distinguish between the three types of sources. They even differ between subjects and disciplines, particularly between the sciences and humanities. By understanding the unique characteristics and features of each, you will be able to identify them and maximize their potential use, and ultimately help you become a more effective researcher and communicate your work to others.
Use Primary Sources:
Encyclopedias, dictionaries, handbooks, guides, directories, classification systems, chronologies, and other factbooks.