2 Kings 15:13

Shallum the son of Jabesh began to reign in the nine and thirtieth year of Uzziah king of Judah; and he reigned a full month in Samaria.

Cross-reference

2 Kings 15:1 establishes Uzziah's reign start, providing the chronological anchor for Shallum's coup in year 39.

1 Kings 16:15 records Zimri's seven-day reign—a parallel pattern of a short-lived usurper in Israel.