Sources of information or evidence are often categorized as primary, secondary, or tertiary material.
These classifications are based on the originality of the material and the proximity of the source or origin.
They are extremely useful in providing a broad overview of a field and usually provide more background information and less technical methodology.
Secondary literature usually has no abstract and the data, figures or images are taken from other sources.
When searching for articles, it's important to know what type of source, or periodical in which the articles are published.
This is beacuse each type has its own purpose, intent, audience, etc.
Examples of secondary sources include reviews, monographs, books, treatises, and manuals.
Primary resources are usually vetted through other researchers who are familiar with the topic. This lends credence and authority to a publication.
Below you will find a description of the three categories of information and examples to help you make a determination.
These sources are records of events or evidence as they are first described or actually happened without any interpretation or commentary.