Hapkemeyer, A. On the principle of dialog in Jochen Gerz's works for public spaces: Andreas Hapkemeyer. Jochen Gerz - Res publica : the public work 1968 - 1999.(1999).

Hapkemeyer, Andreas. "On the Principle of Dialog in Jochen Gerz's Works for Public Spaces: Andreas Hapkemeyer." Jochen Gerz - Res Publica : The Public Work 1968 - 1999.(1999) .

Hapkemeyer, Andreas. "On the Principle of Dialog in Jochen Gerz's Works for Public Spaces: Andreas Hapkemeyer." Jochen Gerz - Res Publica : The Public Work 1968 - 1999.(1999), .