《资治通鉴·唐纪·唐纪二》
夜晚王世充包围偃师，郑守卫偃师，他的部下反而开城放王世充入城。
世充夜围偃师；郑颋守偃师，其部下翻城纳世充。
At an evening hour, Wang Shichong surrounded Yanshi. General Zheng was guarding Yanshi, but his subordinates inside the city actually opened the gates to let Wang Shichong's army inside.