《北史·列传·卷六十七》
接着废除杨侗，将他私下杀害，自己超越本分即皇帝位，建元曰开明，国号为郑。
既而废侗，阴杀之，僭即皇帝位，建元曰开明，国号郑。
He then abolished Yang Dong, killed him in private, transcended his position and became the emperor, established the era name as Kaiming, and named the state Zheng.