Use reference materials, like specialized encyclopedias, to find an overview of your topic & brainstorm ideas.
Try these online databases to search for reference / encyclopedia articles about your topic:
Remember that books & encyclopedias tend to be about broader subjects, so if you have trouble finding something that relates to your topic, try broadening your search terms.
For example, if <sophomores> doesn't give you relevant results, try <undergraduates> or <college students>.