Optional attributes
xlink:title - Human-readable description
xlink:role, xlink:arcrole - URI reference identifies some resource
that describes the intended property
<CLASS_SLIDE xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:show="new"
xlink:role="http://www.cs.rpi.edu/~puninj/XMLJ/slideroles"
xlink:title="XLinks and XPointers"
xlink:href="http://www.cs.rpi.edu/~puninj/XMLJ/classes.xml#
xpointer(/child::*[position()=8]/child::*[position()=first()])">
XLinks and XPointers
</CLASS_SLIDE>
