《资治通鉴·唐纪·唐纪七十七》
丁亥，昭宗颁下诏令，立德王李为皇太子，按成制改名为李裕。
丁亥，诏立德王祐为皇太子，仍更名裕。
On the Dinghai day, Zhaozong promulgates an imperial decree, establishing De Wang Li [his older brother] as crown prince, and renames him Li Yu in line with the standard in effect.