- Author: Juergen Gulbins, Rainer Gulbins
- Language: English
- Year: 2010
- Author: Gulbins Jürgen, Gulbins Rainer
- Language: English
- Year: 2009
- Author: Jürgen Gulbins Rainer Gulbins
- Language: English
- Year: 2009
- Author: Jürgen Gulbins Rainer Gulbins
- Language: English
- Year: 2009