My XPath foo is not yet good enough to figure out how to do the following.

I have an XML that’s similar to:

<?xml version="1.0" encoding="UTF-8"?>
<root>
  <books>
    <book>
      <name>Fantastic World of Peggy</name>
      <category>fiction</category>
      <author-ref>/SanDiego/Peter</author-ref>
    </book>
  </books>
  <cities>
    <name>SanDiego</name>
    <authors>
      <author>
        <name>Peter</name>
        <awards-won>true</awards-won>
      </author>
    </authors>
  </cities>
</root>

Now I want to access all the books where the author has won a prize.

I end up with the following XPath in my mind (which does not work):

//books[category = 'fiction' and //author[name = string-after(<the-current-book>/author-ref, '/SanDiego/') and awards-won = 'true']]

<the-current-book> must be a reference to the book that is the current object in the outside condition.

I can hard-code the cities part as in my XMLs there is only one city but there are many books and many authors.

I have not yet found how to do this in XPath.

Any suggestions on how to do this?