Marking up a simple "and" condition in Boolean operations

Hello experts,

I am trying to perform what ought to be a simple Boolean operation, but I
can't find the answer to this (maybe I'm not looking hard enough).  How do I
mark up a simple *and*?

Input:
<Graphic>
  <Image>t:\common\images\t848586.gif</Image>
  <Caption>NHL Hall of Fame</Caption>
  <NegNumber>556688998h8</NegNumber>
</Graphic>

DTD:
<!ELEMENT Graphic  ((Image | URL),Caption?,NegNumber?) >

As you see.  I might have an instance with Image or URL, and a NegNumber, or
I might have and instance with Image or URL, but no NegNumber.  I want to
code for Image and NegNumber, or Image no NegNumber.

My attempt:
<xsl:template match="Graphic">
  <xsl:choose> 
    <xsl:when test="URL">
  <Graphic URL ="{./URL}">
    <xsl:apply-templates/>
  </Graphic>	
    </xsl:when>
    <xsl:when test="Image"> <!-- I need an "and
                                 NegNumber" test here -->
  <Graphic Image ="{./Image}" NegNumber="{./NegNumber}">
    <xsl:apply-templates/>
  </Graphic>	
    </xsl:when>
    <xsl:when test="Image">
  <Graphic Image ="{./Image}">
    <xsl:apply-templates/>
  </Graphic>	
    </xsl:when>
    <xsl:when test="Negnumber">
  <Graphic NegNumber ="{./NegNumber}">
    <xsl:apply-templates/>
  </Graphic>	
    </xsl:when>
    <xsl:otherwise>
      <Graphic>
    <xsl:apply-templates/>
      </Graphic>
    </xsl:otherwise>
  </xsl:choose>
</xsl:template>

Thanks,

Bryan Schnabel


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