《资治通鉴·晋纪·晋纪三十七》
北方的百姓秦王兴遣使谓裕曰： 慕容氏相与邻好，今晋攻之急，秦已遣铁骑十万屯洛阳；晋军不还，当长驱而进。 
围城益急，张华、封恺皆为裕所获，超请割大岘以南地为籓臣，裕不许。秦王兴遣使谓裕曰： 慕容氏相与邻好，今晋攻之急，秦已遣铁骑十万屯洛阳；晋军不还，当长驱而进。 
The King of Qin from the north, Yao Xing, sent a messenger to Yu saying: The Murong clan and us are good neighbors, and now that Jin is attacking them fiercely, Qin has already sent 100,000 iron cavalry to station in Luoyang; if the Jin army does not return, they should advance directly.