Searching or browsing reference resources provide concise topic overviews and can inform you as to how experts describe the topic you are researching. Many encyclopedia entries cite signature empirical studies and review articles in the the bibliographies, which can lead you to potential sources for your paper.
Books will often provide a broad overview of a topic or a collection of scholarly of articles related to a particular topic. This can help you gain a better understanding of your topic before searching for empirical research articles.