nytpu on Nostr: In formal English writing, should book titles (and other titles) be emphasized, or ...

In formal English writing, should book titles (and other titles) be emphasized, or italisized? i.e. if you're mentioning a title inside a block of emphasized text, should the title be in Roman type like how nested emphasis is marked up, or should the title remain in italics like the surrounding text? I believe the former but it's hard to find a straight answer