- Author: Heike Emmerich
- Language: English
- Year: 2003
- Author: Raschid Ijioui, Heike Emmerich, Michael H Ceyp
- Language: German
- Year: 2007
- Author: Raschid Ijioui Heike Emmerich Michael Ceyp
- Language: German
- Year: 2006
- Author: Raschid Ijioui Heike Emmerich Michael Ceyp Jochen Hagen
- Language: English
- Year: 2009
- Author: Heike Emmerich
- Language: English
- Year: 2003