Similar to RELAX_NG

Office Open XML

Office Open XML file formats

REST

XML Schema (W3C)

Schema for Object-Oriented XML

Simple API for XML

StAX

XAdES

XLink

XPath

XML namespace

XPointer

XQuery

XSLT

Apache Cocoon

XML Encryption

XML external entity attack

Chinese character description languages

XML Base

James Clark (programmer)

XML Signature

Schematron