《后汉书·列传·党锢列传》
桓帝永寿二年，鲜卑侵犯云中，桓帝听说李膺有才能，于是又征召他作度辽将军。
永寿二年，鲜卑寇云中，桓帝闻膺能，乃复征为度辽将军。
In the second year of Emperor Huan's Yongshou, Xianbei invaded Yunzhong. When Emperor Huan heard that Li Ying was capable, he summoned him to be General Duliao.