《旧唐书·本纪·卷八》
夏五月二十三日，嫡长子请求带月俸在兴庆宫建龙池，奉上圣德颂。
夏五月戊寅，宗子请率月俸于兴庆宫建龙池，上《圣德颂》。
On May 23 of the summer, the eldest son requested to build Dragon Pond in Xingqing Palace with a monthly salary and presented the Ode to the Holy Virtue.