XLink, XPointer and XSL
 
 
XLink will provide sophisticated hyperlinking missing in HTML:
- Links that lead user to multiple destinations
 - Bidirectional links
 - Links with special behaviors:
- Expand-in-place / Replace  / Create new window
 - Link on load  / Link on user action
 
 - Link databases
 
XPointer will provide access to arbitrary portions of XML resource
XSL stylesheet language will provide extensibility and transformation facilities (e.g. create a table of contents) 
<commentary xml:link="extended" inline="false">
    <locator href="smith2.1" role="Essay"/>
    <locator href="jones1.4" role="Rebuttal"/>
    <locator href="robin3.2" role="Comparison"/>