《新五代史·列传·杂传第四十二》
沧州节度使卢彦威任李愚为安陵主簿，为母亲服丧解职离去。
沧州节度使卢彦威以愚为安陵主簿，丁母忧解去。
Li Yanwei, the Prefect of Cangzhou appointed Li Yu as the Records Officer of Anling, who resigned from his post and went to mourn for his mother.