Where in the Chicago Manual of Style is the answer to my subject question?
I looked in the CMOS, but could not find the answer to my question.
The book is nonfiction, self help divided into parts with chapters. In headings, the parts are numbered Part I, Part II, Part III, and so on.
If I cross reference within text, what is the CMOS recommendation?
- Recall in part I, ... (roman, same as in headings)
- Recall in part 1, ... (arabic)
- Recall in part one, ... (spelled out)
Note: I know that the overarching rule is consistency and that house style overrules whatever external authority is being used. When developing a house style, it's helpful to know if a style rule is the same as or an exception to CMOS (or other style authority).