This version of Liu's removal was given in the New Book of Tang, which the Zizhi Tongjian adopted as well. See New Book of Tang, vol. 160 and Zizhi Tongjian, vol. 201. However, the Old Book of Tang merely indicated that he had believed that he had grown old and should not be a chancellor any more, and that Emperor Gaozong accepted his resignation in light of that. See Old Book of Tang, vol. 81.
