Citation, Documentation of Sources

Q. I have a student who is using a letter from our archives. The letter is still under the ownership of the author, but the author is probably no longer living. How can my student use Chicago style to create a citation for a letter from the archives when the name of the author is being redacted by the student due to privacy laws?

A. Your student could cite the letter and write “[Redacted]” in place of the author name.