《新唐书·本纪·卷八·穆宗 敬宗 文》
三月初四，幽州卢龙军节度使杨志诚扣押朝廷派来的春衣使边奉鸾，送奚、契丹使尹士恭。
三月辛卯，幽州卢龙军节度使杨志诚执春衣使边奉鸾、送奚契丹使尹士恭。
On the fourth day of the third month, Yang Zhicheng, the Jiedushi of the Yuzhou Lulong Army, detained Bian Fengluan, the spring clothing envoy sent by the imperial court, and sent him to Yin Shigong, the envoy of Xi and Qidan.