《旧唐书·本纪·卷十一》
十二月二十五日，以中书舍人杨炎、秘书少监韦肇都任吏部侍郎，中书舍人常衮任礼部侍郎。
十二月庚寅，以中书舍人杨炎、秘书少监韦肇并为吏部侍郎，中书舍人常衮为礼部待郎。
On the twenty-fifth day of the twelfth month, Yang Yan, the Ritual Attendant of Zhongshu, Wei Zhao, the Secretary of the Ministry of Rites, and Chang Gun, the Ritual Attendant of Zhongshu, were all appointed as the Assistant Minister of Personnel, and Chang Gun was appointed as the Assistant Minister of Rites.