《宋书·列传·卷四十二》
穆之与朱龄石一起处理书信，曾给高祖写回信，从天亮到中午，穆之写了一百函，龄石写了八十函，并且穆之写的都没有废弃。
穆之与硃龄石并便尺牍，常于高祖坐与龄石答书。自旦至日中，穆之得百函，龄石得八十函，而穆之应对无废也。
Muzhi handled the letters together with Zhu Lingzhi, and once wrote a reply letter to Emperor Gao, from dawn to noon, Muzhi wrote a hundred letters, and Lingzhi wrote eighty letters, and none of Muzhi's letters were abandoned.