Mini Example of valid XML Document and DTD

<?xml version="1.0"?>
<!DOCTYPE BOOK [                  
    <!ELEMENT BOOK (P*)>
    <!ELEMENT P (#PCDATA)>
]>

<BOOK>
    <P>chapter 1 - Intro</P>
    <P>chapter 2 - Conclusion</P>
    <P>Index</P>
</BOOK>