A prolific REXX developer that I never had the chance to known, and that I started respecting after reading some of his articles is Richard K. Goran. (Also Dick Goran).
Long time ago I talked to his wife and obtained permission to republish his articles and book on the EDM/2. Now, with the help of a "Dutch OS/2-eCS user" that helped scanning the book, we can finally have his book online.
You can download the book at the EDM/2 Wiki.
Thanks to Dick Goran (1942-1999) and his family.