《管子·乘马》
因此，八十里见方的上等土地与一百二十里见方的下等土地，都相当于一百里见方的中等土地。
以上地方八十里，与下地方百二十里，通于中地方百里。
Therefore, top-grade land with an area of eighty square miles is equivalent to medium-grade land with an area of one hundred square miles, and inferior land with an area of one hundred and twenty square miles.