Create a list of all the title-author pairs, with each pair enclosed in
a result element.
<results>
   FOR $b IN document("http://www.bn.com")/bib/book,
     $t IN $b/title,
     $a IN $b/author
   RETURN
    <result>
     $t,
     $a
    </result>
</results>
  Adapted from XML Query Use Cases