I've just finished a draft DTD for outline exchange in XML. I'd appreciate any feedback anyone has, either here or via e-mail to jbrewer@jera.com.

<!ELEMENT outline (branch*)>
<!ELEMENT branch (body, branch*)>
<!ATTLIST branch
size CDATA #IMPLIED
color CDATA #IMPLIED
face CDATA #IMPLIED
>
<!ELEMENT body (p*)>
<!ATTLIST body
size CDATA #IMPLIED
color CDATA #IMPLIED
face CDATA #IMPLIED
>
<!ENTITY % inline "#PCDATA | i | b | font">
<!ELEMENT p (%inline;)*>
<!ATTLIST p
size CDATA #IMPLIED
color CDATA #IMPLIED
face CDATA #IMPLIED
>
<!ELEMENT i (%inline;)*>
<!ELEMENT b (%inline;)*>
<!ELEMENT font (%inline;)*>
<!ATTLIST font
size CDATA #IMPLIED
color CDATA #IMPLIED
face CDATA #IMPLIED
>

By "face" do you mean "bold" or "Times Roman?" One of them seems missing here.