<bibliography>
<book ISBN="ISBN-10" price="80.00">
<title>Foundations of Databases</title>
<author>Abiteboul</author>
<author>Hull</author>
<author>Vianu</author>
<publisher>Addison Wesley</publisher>
<year>1995</year>
<section>
  <title>Introduction</title>
  In this section, we introduce the concept of XML...
  <section>
    <title>What is XML?</title>
    XML is a hierarchical data model...
  </section>
  <section>
    <title>Why use XML?</title>
    Because Microsoft endorsed it...
  </section>
</section>
<section>
  <title>Conclusion</title>
  Okay, XML rulez!
</section>
</book>
<book ISBN="ISBN-20" price="20.00">
<title>The Lord of the Rings</title>
<author>J. R. R. Tolkien</author>
<publisher>Houghton Mifflin</publisher>
<year>2001</year>
<section>
  <title>Chronicle of Data Models</title>
  On Day 1, man created the relational model;
  On Day 2, man created the extensible markup language (XML)...
</section>
<section>Not that word!</section>
</book>
</bibliography>
