How To Write A Secondary Source Paper . Start with a google search. Some examples of secondary sources: The literature review from www.slideshare.net For example, if you quoted souper’s text, which you found in green’s book, you should reference green because you read green’s book: A secondary source is any source about an event, period, or issue in history that was produced after that event, period or issue has passed. Secondary sources are less easily defined than primary sources.