According to the Library of Congress
"Primary Sources are the raw materials of history, original documents and objects which were created at the time."
"Secondary sources are accounts or interpretations of events created by someone without firsthand experience."
"Tertiary sources present summaries or condensed versions of materials, usually with references back to the primary and/or secondary sources."
|Common Examples of Primary Sources||Common Examples of Secondary Sources||Common Examples of Tertiary Sources|
Indexing and abstracting sources