Historiography is concerned with interpretations and representations of the past as opposed to history itself. It's the critical consideration of the broader cultural, social, economic, and political forces that influence the origins, uses, and biases of sources and of writers themselves. There is no pure, totally impartial historical truth. (from SAGE Encyclopedia of Qualitative Research Methods, 2008).
Finding historiographies on your topic of interest
1) Historiography is often embedded within academic texts writings - sometimes separated out (e.g. literature review) or woven throughout. Search scholarly databases for your topic of interest and look for historiographical elements as your read.
2) Add AND historiograph* to your topic search terms; e.g. canad* AND historiograph* (the * wildcard covers variations like historiography OR historiographies OR historiographical OR historiographer, etc).
Some possible subject headings: Historiography, Historiography -- History, Historiography -- Philosophy
Some starter texts on historiography as a topic itself:
Once you've found some sources, you need to evaluate them to determine whether the information is reliable and relevant to your thesis.
Tutorials (University of Alberta Library)
Critically Analyzing Information Sources (Cornell Univ. Library)
How to Evaluate Journal Articles (Colorado State Univ.)
How to Evaluate a Web Page (Colorado State Univ.)