本文档完整地描述了可扩展标记语言(Extensible Markup Language，XML)，它是标准通用标记语言(Standard Generic Markup Language，SGML)的一个子集。其目的在于使得在Web上能以现有超文本标记语言(Hypertext Markup Language，HTML)的使用方式提供，接收和处理通用的SGML成为可能。XML的设计既考虑了实现的方便性，同时也顾及了与SGML和HTML的互操作性。-integrity of this document

《Prolog Programming in Depth》: In this book, we emphasize practical Prolog programming, not just theory. We present several ready-to-run expert system shells, as well as routines for sorting,searching, natural language processing, and even numeri