《隋书·列传·卷四十九》
从钵室韦向西南走四天路程，就到了深末怛室韦。这个部落因水而得名。
从钵室韦西南四日行，至深末怛室韦，因水为号也。
If you go to the southwest from Bokwishiwei for four days, you will arrive at Shenmodashiwei. This tribe got its name because of the water.