equal-contrib

<xsd:attribute name="equal-contrib" use="optional">
  <xsd:simpleType>
    <xsd:annotation>
      <xsd:documentation/>
    </xsd:annotation>
    <xsd:restriction base="xsd:NMTOKEN">
      <xsd:enumeration value="no"/>
      <xsd:enumeration value="yes"/>
    </xsd:restriction>
  </xsd:simpleType>
</xsd:attribute>