Most of the links on this page are resources (such as databases and catalogs) for finding your literature. You are also likely going to be writing a literature review of your own. Assistant Professor Raul Pachego-Vega writes an amazing blog of writing resources for students, and the section on writing a literature review is especially helpful.
If you are looking for databases carrying material in various languages, consult the International Studies Guide.
These databases are good starting points for finding journal articles.
Doctoral students go through an exhaustive literature search when writing their dissertations. They also tend to work on new questions, sometimes ones that have received very little attention from scholars before. Dissertations often include a section or chapter that is a literature review. You can access many of these dissertations online and benefit from the source lists.