- the GDL bible by David Nicholson Cole
- Download-Link: nottingham.ac.uk
Author: gdl-joe
GDL Onlinekurs
https://www.a-null.com/GDL-Onlinekurs/
- GDL Online Course in German from A-Null
a path through the web to GDL sources
https://www.a-null.com/GDL-Onlinekurs/