《元史·列传·卷九十五》
十六年正月，令高丽国置大灰艾州、东京、柳石、孛落四个驿站。
十六年正月，敕其国置大灰艾州、东京、柳石、孛落四驿。
In the first month of the sixteenth year, Goryeo was ordered to establish four post stations: Daehoeneu-ju, Donggyeong, Yuseok, and Borak.