The 41st volume of Biography of Old Tang Dynasty is a joint biography of Huan, Jinghui, Cui Xuanyong, Zhang Jianzhi and Yuan. The Biography of Jing Hui only said that he had the credit for killing Zhang Yizhi and Zhang Changzong, which had nothing to do with the process; "Yuan Chuan" only said that he participated in the planning activities to kill traitors and participated in the coup; The Biography of Cui Xuanyong simply said that he had the merit of punishing thieves, but did not mention why he had such merit. Biography of Huan is the most detailed description of the dragon coup in Five Biographies and Old Tang Book.