《旧唐书·列传·卷一百零七》
当时因仆射上任时的仪式规定，前后没有定准，中丞李汉奏定制，朝官议论未能通过。
时以仆射上事仪注，前后不定，中丞李汉奏定，朝议未以为允。
At that time, the rituals for when the imperial guards took up their posts were not settled, and imperial censor Li Han submitted a memorial proposing standards, but the court officials who discussed it did not approve.