An ISSN designated by an ISSN Centre to group together the different media versions of a work. Since a single ISSN-L is assigned no matter how many media formats of a work there are, the ISSN-L can be used to link among the different media versions of the work or continuing resource, for example, both the printed and online versions of the work.
<!ELEMENT issn-l (#PCDATA %issn-l-elements;)* >
(#PCDATA)*
Text, numbers, or special characters, zero or more
<element-citation>, <mixed-citation>, <product>, <related-article>, <related-object>
JATS-common1.ent