Historians use the term primary source to describe all sources that are original. Primary sources provide firsthand information that is closest to the object of study.
A secondary source is a source that provides non-original or secondhand data or information.
Turabian, K. L. (2018). A Manual for Writers of Research Papers, Theses, and Dissertations. Ninth Edition. Chicago: University of Chicago Press.
Galvan, J. L. (2013). Writing literature reviews: A guide for students of the social and behavioral sciences. Glendale, CA: Pyrczak.
Persaud, N. (2010). “Primary data source.” In N. Salkind (Ed.), Encyclopedia of research design. (pp. 1095-1098). Thousand Oaks, CA: SAGE Publications, Inc.
“Secondary Source.” (2005). In W. Paul Vogt (Ed.), Dictionary of Statistics & Methodology. (p. 291). Third Edition. Thousand Oaks, CA: SAGE Publications, Inc.
Weidenborner, S. & Caruso, D. (1997). Writing research papers: A guide to the process. New York: St. Martin's Press.