"Glossary, Using Information Resources". Archived from the original on 28 August 2008. ("Tertiary Source" is defined as "reference material that synthesizes work already reported in primary or secondary sources")
uchicago.edu
magazine.uchicago.edu
Kott, Ruth E. "The origins of writing". The University of Chicago Magazine. Retrieved 16 December 2013.
"Glossary, Using Information Resources". Archived from the original on 28 August 2008. ("Tertiary Source" is defined as "reference material that synthesizes work already reported in primary or secondary sources")