Hello Armand,
Next time you post to this list you may want to include a bit more complete
example of the xml instance/fragment you're working with as well as the
desired output.
If you want to iterate over a node set of "katern" elements that must have
one or more "article" child elements you can use the following:
<xsl:for-each select="katern[ article ]">
or,
<xsl:for-each select="katern[ child::*[ article ] ]">
Then within the context of that given for-each you'll have only "katern"
elements that have one or more "article" elements as children.
Cheers,
Jeff
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list