Can lead you to articles, books, dissertations and more from a wide variety of subjects. You can filter to see sources "Available online." Use the Resource Type filter (books are good for in-depth discussion of an issue or leader; reference entries could provide background).
See what a historian has written about the issue/event or the selected leader.
The challenge in finding one research article related to courageous leadership, activism, or social justice will be deciding which one to pick! The possibilities are almost overwhelming. Are there aspects of any of these concepts that are compelling to you? Try adding terms into your search to narrow your results.
Being published in a peer-reviewed journal doesn't necessarily mean it is a research article, but look and see if where you are searching has that filter.
You can also add words into your search that you'd expect to read in the abstract of a research article. Examples include: