All the software in this web page is free. Not only as in free speech, but also as in free beer :-). Seriously speaking, it all has been released under the General Public License (GPL) of the Free Software Foundation, which you may read here.
GDL version 0.3. Source files (23 Kb).
GDL prescription version 0.3. TeX file (6 Kb).
PATOO version 0.1. Linux source files (16 Kb).
PATOO version 0.1. MS-DOS precompiled + Source files (72 Kb).