《汉书·传·萧望之传》
郑朋是楚地的人，心中怀恨，转而要求加入许、史，推脱所说许、史两家坏话的责任说： 这都是周堪、刘更生教给我的，我是关东人，怎么会知道这些呢？ 
朋，楚士，怨恨，更求入许、史，推所言许、史事曰： 皆周堪、刘更生教我，我关东人，何以知此？ 
Zheng Peng was a native of Chu and bore a grudge. He turned to Xu and Shi and tried to shirk responsibility for the slander he had spoken about them, saying: "This was what Zhou Kan and Liu Gengsheng taught me. How would I, a Guandong native, know about these things?"