《隋书·列传·卷十三》
等到高祖病重，杨素和兵部尚书柳述、黄门侍郎元岩等人入宫侍候。
及上不豫，素与兵部尚书柳述、黄门侍郎元岩等入閤侍疾。
When Gaozu fell seriously ill, Yang Su, the Minister of War, Liu Shu, and Yuanshi, the servant in charge of the palace gate, waited on him in the palace.