梁代《魏中经》已佚,阮孝绪述郑默编撰《中经》,所依据的史传没有明言其分类法。郑默校书时主其事者为虞松,处于魏末各项制度“不得妄有改革”之时,不可能改变旧的分类法。晋武帝分秘书图籍为甲乙丙丁四部,使秘书郎四人各掌一部,这可以作为四部分类法起源于荀勖说的新证据。 Liang generation “Wei Zhong Jing” has been lost, Ruanxiao Xu Zheng Mo compilation “in”, based on the history of the Ming did not expressly categorized. At the time when Zheng Mo was a school student, Yu Song was at the core of the book. At the time of the Wei system, “there was no prevarication”, it was impossible to change the old taxonomy. Jin Wu Di Secretary of the Secretary for the Secretary for the Secretary for the four B, Secretary Lilang four palm each one, which can be used as a four-parted law originated in Xun Xun said new evidence.