The following detail the changes made to the DTD in the 2001-04-02 DTD update. See also the change log.
questiongroup has been given an id attribute. questiongroup also now allows subjectgroup as a sub-element.
span now allows object as a sub-element so that inline figures can appear within a span (e.g. in a figure legend)
p now allows bookdetails as a sub-element so that in-line references to books can be tagged. An example is:
