《新五代史·附录·四夷附录第一》
定州王处直怕镇州一旦失去，晋兵必定会合力攻打自己，就派他的儿子王郁游说契丹，让他们进入长城牵制晋兵。
定州王处直惧镇且亡，晋兵必并击己，遣其子郁说契丹，使入塞以牵晋兵。
Wang Chuzhi, the jiedushi of Dingzhou, feared that once Zhenzhou fell, the Jin army would definitely join forces to attack his own territory. Therefore, he sent his son, Wang Yu, to persuade the Khitan to enter the Great Wall and contain the Jin army.