
- Author: David Garfield Daniel Mackler
- Language: English
- Year: 2008

- Author: Doris Bischof-Kohler Fre
- Language: German
- Year: 2011

- Author: Meike Landmann Bernhard Schmitz
- Language: German
- Year: 2007

- Author: Robin Robertson
- Language: English
- Year: 2009

- Author: Richard Tarnas
- Language: English
- Year: 2006

- Author: Nicholas Tarrier Adrian Wells Gillian Haddock
- Language: English
- Year: 2000

- Author: Doris Bischof-Kohler Fre
- Language: German
- Year: 2011

- Author: Frank-M. Staemmler
- Language: English
- Year: 2009