they are all from IBM alphaWorks + one article
The editor takes as input a given DTD, and automatically builds a palette
containing the elements defined in the DTD.
XML Viewer for Java is a Java application that enables viewing XML data
from various perspectives such as the source of the XML, the DTD for the
XML, the hierarchical structure of the XML data.
Decoding XML and the DTD
This article shows how to create XML DTDs and well-formed, well defined XML
files, which can then be validated by the XML parser of your choice.
XMI Framework -
A simple Java API for saving and loading XMI files, creating XMI DTDs, and
XMI Toolkit -
Java software enabling sharing of Java objects using XML. Includes DTD
generation and code/design interchange among Java, UML, and Rational Rose.