I made one more draft version of the tds document, see http://tug.org/tds/ (html) or ftp://tug.org/tex/tds/ (all formats). I added a reference to Michael Downes' paper in the tug 2001 proceedings (which is going to press soon) and made a few other minor text changes. Barring further comments, I'll make this into 1.0 in a few days. Thanks, karl