《淮南子·人间训》
中山城里的人就将他的儿子烹煮了，还派人送给乐羊一鼎肉羹和他儿子的头颅。乐羊抚摸着头颅，哭泣着说： 这是我的儿啊！ 
中山因烹其子，而遗之鼎羹与其首。乐羊循而泣之曰： 是吾子！ 
The people in Zhongshan City cooked his son and sent them to Le Yang a pot of meat and his son's head. Le Yang touched the head and cried and said: This is my son!