《资治通鉴·唐纪·唐纪六十九》
兵部侍郎、判度支杨严三次上表自诉自己才能短浅，无法办理，言辞极为哀痛悲切，但唐僖宗不予批准。
兵部侍郎、判度支杨严三表自陈才短，不能济办，乞解使务，辞极哀切。诏不许。
Yang Yan, Minister of War and Director of Finances, submitted three memorials, expressing his own lack of talent and his inability to handle the situation in extremely sorrowful and mournful terms, but Emperor Xizong of Tang refused to approve them.