Citation, Documentation of Sources

Q. I have an author listed in the bibliography. Below that entry will be one with the same author plus a second author. Should I use a 3-em dash to represent the repeated name, or should I spell it out?

A. Spell it out. Use the 3-em dash when the author information is entirely the same (but see CMOS 13.72).

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