1 Kings (Author Compiled by Isaiah and Jeremiah from records of Nathan, Gad, Iddo, Ahijah, Jehu and others.)
2:11and the days that David hath reigned over Israel are forty years, in Hebron he hath reigned seven years, and in Jerusalem he hath reigned thirty and three years.
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.