Sources
Relevant quotes from the Jewish Encyclopedia:
A superficial examination of the Books of Kings makes clear the fact that it is a compilation and not an original composition. The compiler, or editor, constantly cites certain of his sources. In the case of Solomon it is "the book of the acts of Solomon" (I Kings xi. 41); for the Northern Kingdom it is "the book of the chronicles of the kings of Israel," which is cited seventeen times, i.e., for all the kings except Jehoram and Hoshea (see, e.g., ib. xv. 31); and for the kings of Judah it is "the book of the chronicles of the kings of Judah," which is cited fifteen times, i.e., for all the kings except Ahaziah, Athaliah, Jehoahaz, Jehoiachin, and Zedekiah (see, e.g., ib. xv. 7). Whether the editor had access to these "chronicles," as they were deposited in the state archives, or simply to a history based upon them, can not with certainty be determined. It is generally assumed that the latter was the case (comp. Kuenen, "Historisch-Kritische Einleitung in die Bücher des Alten Testaments," p. 68, and Cornill, "Einleitung in das Alte Testament," p. 123).
Jewish Encyclopedia, "Book of Kings"
It is clear that Chronicles contains matter taken either directly or indirectly from Kings, because it includes verses inserted by the editor of Kings (compare II Chron. xiv. 1, 2 and I Kings xv. 8, 11). Either Chronicles used Kings and "The Book of the Kings," both of which works used the older "Chronicles" (so Driver, "Introduction to the Literature of the O. T." 6th ed., p. 532), or Chronicles used "The Book of the Kings," which had used both Kings and the older "Chronicles," or works based on them.