Doi only if no page (found myself)

mel47

Hi,
I really search but I never found how to do this simple thing:
I want DOI only if pages is not available.

I'm starting from Harvard1-author-date citation. If I change URL by DOI in this part:
<if variable="DOI">
<text value="DOI:" suffix=" "/>
<text variable="DOI"/>
</if>
I now have a bibliography with DOI for each citations. I just want for those in press. How/where I modify to have a rule "if page does'nt exist, put doi"?
Thanks
Mélanie


EDIT Feel stupid. Just found an other style with the good macro:
<macro name="access">
<choose>
<if variable="volume"/>
<else-if variable="DOI">
<text variable="DOI" prefix=" doi:"/>
</else-if>
<else-if variable="URL">
<text term="at"/>
<text variable="URL" prefix=" <" suffix=">"/>
</else-if>
</choose>
</macro>

adamsmith

(that macro, of course, checks for volume, not for pages, but yes, that's the way to go).