Limiters for primary source documents are available in the EBSCO databases and also in some others like ProQuest. Here is how those options appear:
According to the Library of Congress "Primary Sources are the raw materials of history, original documents and objects which were created at the time."
Searching the term "primary sources" in the library catalog will not yield many results. Use these terms instead:
According to the Library of Congress
"Secondary sources are accounts or interpretations of events created by someone without firsthand experience."
Common Examples of Secondary Sources: