Writing text to a txt-doc using xslt

I have the following xml-doc:

<bibtex:file>
<bibtex:entry id="unopt">
<bibtex:unpublished>
<bibtex:author>BibTeXML team 20</bibtex:author>
<bibtex:title>Unpublished title 20</bibtex:title>
<bibtex:abstract>De samenvatting 20</bibtex:abstract>
</bibtex:unpublished>
</bibtex:entry>
...
</bibtex:file>

Now I have to write the content of bibtex:abstract to a new txt-file.

How do I do that and how do I give the file the name I want?

Thanks already.

The answer is that it depends on which XSLT parser tool
you are using.

You need to tell us what parser you are using.

- Finnbarr

Since I was allowed to use only true xslt-commands and no parser-specific commands I had to find a different way and I did!
I used xsl:document from version 1.1 and this works perfectly.
My code now looks like this:

<xsl:document href="documenten/{$ID}.txt" format="txt">
<xsl:value-of select="bibtex:abstract"/>
</xsl:document>

But thanks for your attempt to help me.