《史记·三十世家·管蔡世家》
十五年，宋灭掉曹，抓曹伯阳和公孙强回宋杀掉，曹国就灭亡了。
十五年，宋灭曹，执曹伯阳及公孙强以归而杀之。曹遂绝其祀。
In the fifteenth year Song destroyed Cao, captured Cao Boyang and Gongsun Qiang and executed them in the State of Song. The State of Cao was destroyed.