《元史·列传·卷六十二》
 世祖之制：凡有田者均服劳役，土地买卖，随土地征发劳役。
世祖之制，凡有田者悉役之，民典卖田，随收入户。
Decree of Emperor Shizu: All landowners are to be subject to corvée. Taxes on sale of land are to be paid simultaneously with land corvée.