《元史·本纪·卷七》
上都地域遥远，商旅不容易往返，特地免收该地区赋税以示优待，只须买卖田庄房屋、奴仆婢女、牲畜，按常例收取契约的工本费。
上都地里遥远，商旅往来不易，特免收税以优之，惟市易庄宅、奴婢、孳畜，例收契本工墨之费。
Shangdu is located in a remote area, and it is not easy for merchants to travel back and forth. The region is exempted from taxes to show favoritism. Taxes are only levied on the sale of land, houses, slaves, maidservants, and livestock, according to the usual practice. The cost of the contract is collected.