Here you can download grammar fragments that correspond to chapters in Head-Driven Phrase Structure Grammar: Eine Einführung.
In order to work with the fragments you have to install the grammar development system TRALE. TRALE is freely available, but requires SICStus-Prolog. Please ask Frank Richter for the TRALE code. There are also runtime executables that can be used without SICStus. The grammars and Trale runtime executables can also be found on the Grammix CD Rom, which is free for non-commercial purposes.
With TRALE you can