《隋书·列传·卷四十九》
从北室韦继续向北走上千里，便是钵室韦。这里的人靠近胡布山居住，人口比北室韦要多，不知究竟分为多少个部落。
又北行千里，至钵室韦，依胡布山而住，人众多北室韦，不知为几部落。
If you continue walking from Northern Shiwei to the North for a thousand miles, you will reach Bokwishiwei. People here live near the Hubu Mountain. The population is larger than the Northern Shiwei. You don't know how many tribes they are divided into.