In order to gain a more complete picture of your issue and understand how historians have interpreted your topic of interest, you will want to locate secondary sources.
Secondary Sources interpret and/or analyze events, facts and primary sources. From a date perspective they are usually one or two steps removed from the event. Most of the time, in academia, "scholarly sources" are preferred, i.e. sources that have been peer-reviewed, include documentation (footnotes/endnotes), critical analsysis and/or studies. In the fields of History and Journalism there are several library databases/indexes that identify these materials including:
Adapted from University Library, California State University, Los Angeles. "Differences between Books / Articles, Scholarly Journals / Magazines, Primary Sources / Secondary Sources " Guide
http://web.calstatela.edu/library/guides/History-Guide.pdf
