John Gill Commentary 2 Kings 15:26

"Now the rest of the acts of Pekahiah, and all that he did, behold, they are written in the book of the chronicles of the kings of Israel." — 2 Kings 15:26 (ASV)

And the rest of the acts of Pekahiah
The same form of expression is used as before, (2 Kings 15:21) , of all the kings.