Yes, that sounds like a different category from Chicago. Same category as Style: Lessons in Clarity and Grace. I flipped open Chicago to an arbitrary page, and

Yes, that sounds like a different category from Chicago. Same category as Style: Lessons in Clarity and Grace. I flipped open Chicago to an arbitrary page, and it was describing how to refer to decades—whether you say ’90s or nineties or 1990s. It had rules for whether to use an apostrophe, whether to capitalize, and whether to spell out or use numerals.