《宋史·列传·卷八十六》
免役法，根据百姓家庭财产多少，分别令他们出钱雇人充役，下至单丁户、女户，本来不要服役的家庭，也一概出钱，叫助役钱。
免役之法，据家赀高下，各令出钱雇人充役，下至单丁、女户，本来无役者，亦一概输钱，谓之助役钱。
The Tax Exemption Policy required people to pay money and hire others to serve according to the amount of their family property. Even the households with only one man or only women, which were originally not required to serve, had to pay money called "supplementary service money."