Jiu Tangshu vol 194 upper [1] "可汗者，猶古之單于；[...] 其子弟謂之特[勤] (ms. 特勒)" Tr. "the Kehan, in the past, was called Chanyu: [...] His sons and younger brothers are called Te[qin] (ms. Tele)"(in Chinese)
Xin Tangshu Vol. 215 upper [2] (in Chinese) "至吐門，遂強大，更號可汗，猶單於也，[..] 子弟曰特[勤] (ms. 特勒)" tr. "Till Tumen, [who] has achieved strength and greatness and is now called Kehan, formerly Chanyu, [...] [his] sons and younger brothers are called Te[qin] (ms. Tele)
