《隋书·列传·卷四十》
太子杨勇听说此事就召见他，等他到了京城，皇帝又诏令他侍奉蜀王杨秀，他故意拖延不到任。
太子勇闻而召之，既至京师，敕令事蜀王秀，迁延不往。
Crown Prince Yang Yong heard about this and summoned him, but when he reached the capital, the emperor ordered him to serve King Shu of Yang Xiu, so he deliberately delayed and did not report his arrival.