《资治通鉴·唐纪·唐纪三》
宇文士及随宇文化及到黎阳，高祖亲笔写诏书召宇文士及，宇文士及暗中派家僮从小路赴长安，又托使者献金环表示想回长安。
士及从化及至黎阳，上手诏召之，士及潜遣家僮间道诣长安，又因使者献金环。
Yu Wenshi followed Yu Hua Ji to Liyang, Emperor Gaozu personally wrote an imperial edict to summon Yu Wenshi, who secretly sent a manservant to take a circuitous route to Chang'an and also asked a messenger to present a gold chariot-bearing staff to signify his desire to return to the Tang capital.