XML-DTD help/clarification needed

I have the following xml syntax which I'm creating inline DTD for.

<article title="Article here?" id="a2">
    <authors>
        <author>Robert Van</author>
        <author>Michael Gordan</author>
    </authors>
    <journal>
        <name>Metaphysics</name>
        <volume>1</volume>
        <issue>2</issue>
        <published>05/25/2013</published>
        <pages start="355" end="365"/>
    </journal>
</article>

I have coded the following DTD commands:

    <!DOCTYPE articles [
    <!ELEMENT articles (article+)>
    <!ELEMENT article (authors+,journal+)>
    <!ELEMENT authors (author)>
    <!ELEMENT journal (name, volume,issue,published,pages,url)>

      ]>

however I get a lot of errors, I'm assuming the way I decalred pages and url are wrong? Can someone help please?