I've released a preliminary version of the dtd-types package: http://projects.haskell.org/dtd/ I originally intended these types to be eventually incorporated into John's xml-types package. However, after writing them, I now see that there is actually very little in common. The feel of a DTD is quite different than XML itself. The only type from xml-types that I actually used was EntityID, which is a very minor. As John pointed out, it is very unusual to find internal DTD subsets in XML documents in the wild. And I find that my own code involving external DTDs has little to do with my code for XML in practice, even though the two are of course complimentary in purpose. However, if people feel that this shouldn't be a separate package, I'd be happy to deprecate it. Of course, I am eager for any comments and suggestions about the types themselves. Thanks, Yitz