Eliminating duplicate search results

------------------------------------------------------------
   <gedicht>
     <id>gedicht_20071204_fopstronk</id>
     <titel>Fopstronk</titel>
     <jaar>2007</jaar>
     <maand>12</maand>
     <dag>04</dag>
     <strofen>
       <regel>omdat jij niet oplet</regel>
       <regel>doe ik het snel</regel>
       <regel>&#160;</regel>
       <regel>want als jij niet</regel>
       <regel>dan ik wel</regel>
     </strofen>
     <plaats></plaats>
     <commentaar></commentaar>
   </gedicht>
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. Now, for each occurrence of a search query value within an element <regel>
(line) I want to see the contents of the parent element <titel> (title).

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<xsl:for-each select="strofen/regel">
<xsl:variable name="line" select="."/>
<xsl:variable name="linelow"
select="translate($line,'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz')"/>
 <xsl:if test="contains($linelow,$querylow)">
  <xsl:copy-of select="../../titel" />
  <br />
 </xsl:if>
</xsl:for-each>
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. However, this returns 1 title for each line containing the query. This
leads to multiple occurrences of the same title, as the query can be present
in multiple lines of 1 poem. As is visible in my output:

which should, I think, solve my problem. But I cannot figure out how to
translate it into something that works in my situation.

Kafai Publishing
Michiel F.E. van Reenen
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