(DT*, DD?)+ is almost certainly an illegal content model, because it's
ambiguous (in the SGML sense). The changed version doesn't express the
intent, but does match the same set of patterns, in a legal way.
* (LI)+ => (LI)* in OL and UL: why?
so that an automatically generated list can be empty; someone in
Chicago [who? where are the minutes when you need them? :-)] argued
v. strongly for this, and I think it's reasonable.
Lee