《旧唐书·本纪·卷十五》
十一月二十一日，任命御史中丞胡证为单于大都护、振武军、麟胜军等军节度使。
甲午，以御史中丞胡证为单于大都护、振武麟胜等军节度使。
On the 21st of November, Yushi Zhongcheng Hu Zheng was appointed as Shanyu Daduhu and the Jiedushi of Zhenwu and Linsheng, among other armies.