《隋书·列传·卷十》
因此派人去找杨勇，还没来得及派使臣，高祖就突然死了，杨广隐瞒着不发丧。
炀帝践极，俨常从行，卒于道，实鸩之也。
So he sent someone to look for Yang Yong, but before the emissary could be dispatched, Gaozu died suddenly, and Yang Guang concealed the news and did not issue a funeral announcement.