Use MRU’s LibrarySearch (main search box, library homepage).
Add terms to the search that describe your topic/character/comic
e.g., women, superheroes, criticism, history, 1970s, etc.
Not all characters/comics/themes/issues will have been studied, so you may need to improvise. Be prepared to broaden and narrow your search terms as needed.
Or search directly in any of the recommended databases listed below.
The MLA Handbook (9th ed.) has two examples for how to cite comics:
See also MLA's guidance on citing specific panels in a comic.