《资治通鉴·唐纪·唐纪四十五》
当时供给德宗的粮食，仅有粗米二斛，官吏每每窥伺敌军的休息时间，夜里将人系在绳索上放到城外，去采集蔓菁根，献给皇上。
时供御才有粝米二斛，每伺贼之休息，夜，缒人于城外，采芜菁根而进之。
At that time, the only food available for Emperor Dezong was 2 bushels of coarse rice, and the officials would often observe the enemy's sleeping hours, and lower a man outside the city on a rope at night to gather turnip roots, which they would then offer to the emperor.