en_tn_lite_do_not_use/1ki/15/23.md

are they not written in the book of the events of the kings of Judah?

This question is used to either inform or remind the readers that the information about Abijah is in this other book. See how you translated this in 1 Kings 14:29. This rhetorical question can be translated as a statement. AT: "they are written in the book of the events of the kings of Judah" (See: rc://en/ta/man/translate/figs-rquestion)

are they not written in the book of the events of the kings of Judah?

This can be stated in active form. AT: "someone has written about this in the book of the events of the kings of Judah." (See: rc://en/ta/man/translate/figs-activepassive)