Error out if no title
diff --git a/xslt/epub2i5.xsl b/xslt/epub2i5.xsl
index e3d5012..d6d9aba 100644
--- a/xslt/epub2i5.xsl
+++ b/xslt/epub2i5.xsl
@@ -226,6 +226,10 @@
<xsl:message terminate="yes">ERROR: No dc:date found for ISBN: <xsl:value-of select="$isbn"/></xsl:message>
</xsl:if>
+ <xsl:if test="not(normalize-space($titel))">
+ <xsl:message terminate="yes">ERROR: No title found for ISBN: <xsl:value-of select="$isbn"/></xsl:message>
+ </xsl:if>
+
<idsDoc TEIform="TEI.2" type="text" version="1.0">
<idsHeader TEIform="teiHeader" pattern="text" status="new" type="document" version="1.1">
<fileDesc>