This sample will include the content of the /html/body tag of the file sample.xhtml. This is done using the custom 'elementpath' XPointer scheme, which avoids building a DOM (which the xpointer() scheme does).
<xi:include href="sample.xhtml" xpointer="xmlns(c=http://apache.org/cocoon/xpointer)c:elementpath(/html/body)"/>
Hello, this is the content of the sample.xhtml file.
And here's yet another paragraph from that file.