《北史·列传·卷十六》
献文帝想要将帝位传给京兆王子推，当时源贺统率大军屯兵大漠以南，皇上让人飞骑召源贺回京。
及献文将传位于京兆王子推，时贺都督诸军事屯漠南，乃驰传征贺。
Emperor Xiaowen wanted to pass the throne to the Prince of Jingzhao, Yuan He, at that time, he was leading a large army stationed to the south of the Great Desert, the emperor sent a flying messenger to call Yuan He back to the capital.