◇◆

%issn-elements; ISSN Elements

Elements that can be included along with data characters inside the content model of the <issn> element.

Usage/Remarks

This parameter entity is currently set as a null string, i.e., there is no string content. However, a customization module could redefine this parameter entity, thereby adding elements to the <issn> element.
Declaration
<!ENTITY % issn-elements
                        ""                                           >