Railway applications - designation systematic for rail vehicles - part 3 : classification of documents , corrigenda to din 25002 - 3 : 2001 - 09 铁路设施.铁路车辆的命名制度.第3部分:文献分类. din 2
Further and further subdivision of the categories is neither good for readers ' retrieval , nor good for stable development o the classification system 摘要类目划分层次过于深入，无益于读者的检索，不利于分类法类目体系的稳定发展，也给文献分类标引增加了不必要的难度。
Content analysis and document classification must follow the logical rules of classification , but the classification of contents from micro - degree ; it is good for getting competitive information by content analysis ; it is good for strengthening the reliability and accuracy of book review and improving review value and academic value 内容分析法与文献分类都必须遵守分类的逻辑原则，但内容分析的分类从微观角度透视各种载体内容；运用内容分析有利于获得竞争情报；有利于增强书评的客观性精确性，提高评论价值与学术价值。
