Cross reference
Judges 12:9
9 and he hath thirty sons and thirty daughters, he hath sent without and thirty daughters hath brought in to his sons from without; and he judgeth Israel seven years.
Judges 10:4
4 and he hath thirty sons riding on thirty ass-colts, and they have thirty cities, (they call them Havoth-Jair unto this day), which `are' in the land of Gilead;
Judges 12:14
14 and he hath forty sons, and thirty grandsons, riding on seventy ass-colts, and he judgeth Israel eight years.