《资治通鉴·后晋纪·后晋纪六》
契丹使瀛州刺史刘延祚给后晋乐寿监军王峦写信，要求率全城归降，并且说： 城中契丹兵不足一千人，请朝廷派轻兵前来袭击，自己为内应。
契丹使瀛州刺史刘延祚遗乐寿监军王峦书，请举城内附。且云： 城中契丹兵不满千人，乞朝廷发轻兵袭之，己为内应。
The Khitan envoy Liu Yanzhuo, the Prefect of Yingzhou, wrote a letter to Wang Luan, the Inspector of the Later Jin Leshou, asking him to lead the entire city to surrender, and said:  There are less than 1,000 Khitan soldiers in the city. Please ask the court to send light troops to attack, and I will be an insider.