- Discussion on Necessity for Obsoleting Backward Seamless Steel Tube-making Equipment at Home in Terms of Production Setup and Dependence on Export of Seamless Steel Tube Industry
从无缝钢管生产格局和出口依存度现状分析我国淘汰落后无缝钢管装备的必要性 - Newer media are obsoleting the book.
更新的传播媒介正在逐步淘汰书籍。