《资治通鉴·后晋纪·后晋纪六》
还有，今年秋天雨多，从瓦桥以北，积水漫无边际，契丹主已回牙帐去了，纵然听到关南有突变，路远隔水，也不能前来援救。 
又，今秋多雨，自瓦桥已北，积水无际，契丹主已归牙帐，虽闻关南有变，地远阻水，不能救也。 
In addition, there was a lot of rain this autumn. From the north of Wqiao, the water accumulated and spread without bounds. The Khitan Lord had returned to his tent. Even if he heard that there was a sudden change south of the pass, he would not be able to come to the rescue due to the long distance and the water.