《资治通鉴·宋纪·宋纪十四》
献文帝命令根据人民的贫富分为三等，作为征收赋税的标准，每等再分三级，上三级运到平城，中三级运到其他各州，下三级则运到本州州府。
显祖命因民贫富，为三等输租之法，等为三品：上三品输平城，中输它州，下输本州。
Emperor Xianwen ordered the people to be divided into three ranks according to their wealth to serve as the standard for collecting taxes. Each rank would then be divided into three levels. The top three levels would be sent to Pingcheng, the middle three levels would be sent to various states, and the bottom three levels would be sent to the state capitals.