Recommended brief Reference sources:
NOTE: Hundreds more articles may be available on Scotus that are not full-text online, but available from our library or via Interlibrary loan. Simply use the online catalog as follows: If you are looking for books/articles written BY or About Scotus, you should search our online catalog or databases for this entry: John Duns Scotus approximately 1266-1308,. or search for Subjects related to him ("Theology Middle Ages", "Scholasticism" or "Scotism" for example).
Here's a link to Books on Scotus and his theology available at Luther Sem; many others available by interlibrary loan in Minnesota (Minitex)
Also consult the following databases for helpful articles or abstracts on Scotus (both JSTOR and Open Access Theological Library have hundreds of book chapters or articles on Scotus. For example, see "Scotus" in JSTOR
Duns Scotus in the Post-Reformation Digital Library
For digital resources, including rare manuscripts, on/of Scotus, see the Digital Vatican Library