《新唐书·列传·卷七十八》
肃宗已在灵武登上了皇帝位。真卿多次派使者带着用蜡丸封的信向皇帝汇报军政事务，拜为工部尚书兼御史大夫，复任河北招讨使。
肃宗已即位灵武，真卿数遣使以蜡丸裹书陈事。拜工部尚书兼御史大夫，复为河北招讨使。
Emperor Suzong had ascended the throne in Lingwu. Zhenqing repeatedly sent messengers with letters sealed in balls of wax to report on military and political affairs to the emperor, was appointed Minister of Works and Imperial Censor, and resumed his position as Commissioner to Pacify Hebei.