《北史·列传·卷二十四》
后来，文帝对杨素、牛弘说： 道衡年纪大了，我不能再驱使他，使他尝受辛劳，应该派卫士守卫着他家的大门，让他过上安逸稳定的日子。 
后帝谓杨素、牛弘曰：道衡老矣，驱使勤劳，宜使硃门陈戟。 
Later, Emperor Wen said to Yang Su and Niu Hong, "Daoheng is old, and I can no longer drive him to work hard. I should send a guard to guard his family, so that he can live a peaceful and stable life."