《资治通鉴·唐纪·唐纪四十六》
滑州刺史李澄秘密派来使者请求归降，德宗答应任命李澄为汴、滑节度使。
滑州刺史李澄密遣使请降，上许以澄为汴滑节度使。
Li Cheng, the governor of Hua Prefecture, secretly sent an envoy to ask for surrender, and Emperor Dezong agreed to appoint Li Cheng as the Jiedushi of Bian and Hua.