《资治通鉴·唐纪·唐纪六十二》
诏令又说，皇太子李成美尚年幼，没有经过老师的训导，仍封为陈王。
且言太子成美年尚冲幼，未渐师资，可复封陈王。
The imperial edict also said that Crown Prince Li Chengmei is too young and has not yet been taught by teachers, he would be crowned as Prince Chen instead.