System

Standards:

AIXM - Aviatory XML
DOM - Document Object Model
DTD schemas (Document type Definition)
SAX - Simple API for XML
XML Infoset
XPath
XSL

XML Parser Error Codes - IBM Documentation XML Programming Interfaces

XML Parts

elements, atributes, PCDATA a document id

Data Types

XML Schema Part 2: Datatypes Second Edition

Standardy rodiny XML https://www.fi.muni.cz/~tomp/slides/pb138/1std-terminology/standards/toc.html

XML exampleshttp://www.w3schools.com/xml/xml_examples.asp
DrugBank Release Version 5.1.12 | DrugBank Online

Journey to the Center of the DrugBank XML Database - part 1 - DataScienceCentral.com

XML Code Project https://www.codeproject.com/KB/XML/
XML Archives https://listserv.heanet.ie/cgi-bin/wa?A0=XML-L

XML Editors

Comparison of XML editors - Wikipedia

XML command-line tools for manipulating structured text data

Xidel - HTML/XML/JSON data extraction tool

XML Editor/Viewer Online - xmlGrid.net

How-TO PDF publishing http://cocoon.apache.org/2.0/howto/howto-html-pdf-publishing.html