《新唐书·列传·卷一百四十六》
伏允害怕了，引一千多骑兵逃入大碛中，人渐渐走散，随从者最后只有百把人，窘迫无以解脱，乃自缢而死。
伏允惧，引千余骑遁碛中，众稍亡，从者才百骑，穷无聊，即自经死。
Fu Yun was scared and led more than 1,000 cavalry to escape into the great desert, people were gradually separated, and only a hundred or so followers were left. He was in a desperate situation with no solution, so he hanged himself.