%thead.content;
Table Header Element (thead) Content
Defines what elements can occur within the <thead> element in NISO JATS tables.
Remarks
The NISO JATS table model parameter entity is used in the same way as the equivalent
parameter entity in the XHTML 1.1 table model. Since this parameter entity was named
in the same way as the XHTML 1.1 Tag Set equivalent, it does not follow
the naming conventions for this Tag Set: it is in mixed (not lower) case, and the
separator character is a period, not a hyphen.
Model
<!ENTITY % thead.content "( %tr.qname; )+" >
Expanded Model
( tr )+