Citation, Documentation of Sources

Q. What is the correct way to format a note citation for a chapter from an edited book when the editor and the author happen to be the same person?

A. Cite it as a contribution to a multiauthor book and put the author’s name twice, where the author and editor names go. See also CMOS 14.9.

[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]