《宋史·列传·卷四十四》
昌朝援引汉代发生灾异时册封罢免三公的成例，上表奏请求免职。
昌朝引汉灾异册免三公故事，上表乞罢。
Chang Chao cited the example of the Han dynasty's dismissing the Three Dukes when disasters had occurred, and requested to be relieved of his post in a petition.