《旧五代史·后梁·列传十三》
原定所在地方同一天暗自发兵，但事情大多泄露，只有刘鄩率领偏师攻陷了兖州城，于是占据了兖州。开始，刘鄩派细作装扮成卖油的人，侦察兖州城内虚实以及进入的道路，看到外城下面有一水洞可以带着部队进城，就记住这个地方。
《金华子》云：鄩入据子城，甲兵精锐，城内人皆束手，莫敢旅拒。
On the same day, the troops were sent out secretly from the original place, but most of the things were leaked. Only Liu Pi led a partial division to capture the city of Yanzhou, and then occupied Yanzhou. At first, Liu Pi sent spies disguised as oil vendors to spy on the truth of Yanzhou City and the way in. Seeing that there was a water cave under the outer city, he could take the troops into the city, so he remembered this place.