《陈书·列传·卷二十七》
郑灼家贫，他抄写义疏日以继夜，笔毫用尽，每次都削而用之。
灼家贫，抄义疏以日继夜，笔毫尽，每削用之。
Zheng Zuo was poor, so he copied the edict day and night, using up all his writing brushes and having to carve them into shape to continue using them.