Nested FLWOR Queries

For each book in the bibliography, list the title and authors, grouped inside a result element.

<results>
 {
   for $b in doc("bib.xml")/bib/book
     return
      <result>
       { $b/title }
       {  
         for $a in $b/author
         return $a
       }
      </result>
 }
</results>

Adapted from XML Query Use Cases