Correct XSLT syntax for Google multilingual sitemaps/ xhtml:link

I have an XML sitemap for a multilingual site that follows Google's specifications for multilingual sitemaps using the xhtml:link tags.

The syntax looks like this:

        <url>
          <loc>http://www.example.com/url-segment/</loc>
          <xhtml:link rel="alternate" hreflang="en" href="http://www.example.com/url-segment/" />
          <xhtml:link rel="alternate" hreflang="de" href="http://www.example.com/de/url-segment/" />
          <xhtml:link rel="alternate" hreflang="fr" href="http://www.example.com/fr/url-segment/" />
          <lastmod>2016-08-09T00:41:57+12:00</lastmod>
          <changefreq>weekly</changefreq>
          <priority>0.9</priority>
        </url>

I'm trying to make this human readable for the client using an XSLT template like this:

  <xsl:for-each select="sitemap:urlset/sitemap:url">
    <tr>
      <td>
        <xsl:variable name="itemURL">
          <xsl:value-of select="sitemap:loc"/>
        </xsl:variable>
      </td>
    <td>
      <xsl:value-of select="concat(sitemap:priority*100,'%')"/>
    </td>
    <td>
      <xsl:value-of select="concat(translate(substring(sitemap:changefreq, 1, 1),concat($lower, $upper),concat($upper, $lower)),substring(sitemap:changefreq, 2))"/>
     </td>
     <td>
       <xsl:value-of select="concat(substring(sitemap:lastmod,0,11),concat(' ', substring(sitemap:lastmod,12,5)))"/>
     </td>
   </tr>
 </xsl:for-each>

Which works without the xhtml:link tags. But I'm not sure how to correctly reference the xhtml:link tags. I've tried something like this:

<xsl:for-each select="xhtml:link">
  <tr>
    <td>
      <xsl:value-of select="xhtml:link@href"/>
    </td>
    <td>
      <xsl:value-of select="xhtml:link@hreflang"/>
    </td>
    <td colspan="2"></td>
  </tr>
</xsl:for-each>

But that's not working.

What is the correct XSLT syntax for looping through/ selecting xhtml:link tags in Google multilingual sitemaps?