Removing duplicates in xml with xslt

Question

I need to remove duplicates in the following xml:

Answer 1

This task can be easily achieved using standard grouping solutions. Do not use single select statements to do that which are well known to cause performance problems.

Note The reference to identity.xsl just include into the stylesheet the well known identity transformation template.

[XSLT 1.0]

[XSLT 2.0]