CMoS CSL modification for Zotero

excerpt.xml

<!-- Insert at line 761 to use month and year if there is an issue
     number, and just year if there is no issue. If you prefer to only
     ever use the year, replace the <choose> block with: 
       <date variable="issued" form="numeric" date-parts="year"/>
-->
          <if type="article-journal" match="any">
            <group delimiter=" ">
              <choose>
                <if variable="volume issue" match="all">
                  <date variable="issued" form="text" date-parts="year-month"/>
                </if>
                <else>
                  <date variable="issued" form="numeric" date-parts="year"/>
                </else>
              </choose>
            </group>
          </if>