Is there a database that allows me to search footnotes?
You can determine which articles have cited a particular author in an earlier or current publication by searching Web of Science multidisciplinary database.
Click on: "Cited Reference Search. Find the articles that cite a person's work" link. Enter the author's name.
As you get results: "Select cited references and click "Finish Search." button.
You will retrieve a list of articles that cite the author and his/her work.