Most research articles will list the author's (or authors') affiliation - the place where they work - somewhere on the article. You may find it on the first page, or it may be all the way at the end. See an example at the bottom of this page.
Here are a few good ways to look for articles published by APUS faculty and staff:
Just remember to double-check for American Public University System listed as the author's affiliation, as in the example below, rather than simply mentioned somewhere in the article itself.