Content model for the <ack> element
<!ENTITY % ack-model "(label?, title?, (%abstract.class;)*, (%kwd-group.class;)*, (%just-para.class;)*, (%sec.class;)*, (%ref-list.class;)* )" >
(label?, title?, (abstract)*, (kwd-group)*, (p)*, (sec)*, (ref-list)* )
JATS-journalpubcustom-models1.ent