Literature reviews use a combination of primary and secondary sources -- the purpose of a LR is to document and analyze what has been published on any given topic through time.
The sources are: print, electronic or visual materials necessary for your research.
Sources are classified into primary, secondary and tertiary.
Watch this short video from University of Victoria for more details:
Note: A source can be considered a primary source if it was created during a particular time, and it is documenting the "contemporary thinking" of that period.
A literature review is a comprehensive survey of the scholarly research (e.g. articles, books, dissertations, conference proceedings) published on a specific topic, providing a description, summary, and critical evaluation of each work.. It is:
The purpose of the literature review is to offer an account of how a topic has been researched and written about in the past and should identify and provide commentary on the processes and data sources that were used to reach the findings presented in the past research.
It should also feature analysis of how past research projects have influenced the current understanding of the topic.
Finally, a literature review should offer insight into how the topic can be further explored and researched in the future.
The four steps of the literature review process are:
These four steps are discussed in depth on subsequent pages of this guide.