"It’s best to be more straightforward and specific. For example, use bullets or boldface zeros (••• or 000) to stand in for page numbers that cannot be determined until a manuscript is paginated as a book (but see paragraph 2.37 in CMOS). For items like missing figures, describe exactly what’s missing. In electronic environments, you have recourse to comment features, like the syntax of SGML, which allows for descriptive instructions that will not interfere with the final version of a document. "〔(Chicago Style Q&A )〕