《三国志·蜀书·先主传》
建安十二年，曹公往北争讨乌丸，先主劝说刘表攻袭许县，刘表没有听从。
十二年，曹公北征乌丸，先主说表袭许，表不能用。
In the twelfth year of Jian'an, Cao Gong went north to fight against Wuhuan. The former Master persuaded Liu Biao to attack Xuxian, but Liu Biao did not listen.