《史记·七十列传·平津侯主父列传》
现在外郡的土地有几千里，列城数十个，地理山川的形势可以控制百姓，胁迫附近的诸侯，这不是公室皇家的利益。
今外郡之地或几千里，列城数十，形束壤制，旁胁诸侯，非公室之利也。
Now the land of the outlying counties is several thousand li, there are dozens of towns, and the geographical landscape can control the people and coerce the neighboring princes. This is not the interest of the royal family.