《新唐书·列传·卷一百一十》
时间长了，看守的人懈怠了，他就逃到河中，用绢写奏章，派人抄小路送到蜀地。
久之，守者懈，乃奔河中，裂缣书章，遣人间走蜀。
After a long time, the guards became lazy, so he escaped into the river, wrote the report on silk, and asked someone to take the small road to the Shu region.