12.1. The include Element

The key component of XInclude is the include element. This must be in the http://www.w3.org/2001/XInclude namespace. The xi or xinclude prefixes are customary, although, as always, the prefix can change as long as the URI remains the same. This element has an href attribute that contains a URL pointing to the document to include. For example, this element includes the document found at the relative URL AlanTuring.xml:

<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" 
            href="AlanTuring.xml"/>