These databases contain primary source materials:
A primary source is the uninterpreted original document that contains the words of the witnesses or the first recorders of an event or creative work. Some examples of primary sources:
Artifacts (clothing, furniture, tools, buildings)
Experiments
First–person accounts (including newspaper accounts)
Government publications (statistics, court reports)
Historical documents
Internet resources (especially digitized versions of historical documents)
Lab reports
Manuscripts, journals, diaries
Observations
Official papers
Recordings