《隋书·列传·卷四十》
少年以聪慧敏捷为人称道，与信都的刘焯潜心读书，十年不曾出门。
少以聪敏见称，与信都刘焯闭户读书，十年不出。
In his youth, he was known for being quick-witted and agile; he studied avidly with Liu Zhao from Xin du, and they did not leave their homes for ten years.