- Author: Hansen William B., Scheier Lawrence M
- Language: English
- Year: 2014
- Author: Claus Vester cc-live, Juul Jesper, Vester Claus, Voelchert Mathias
- Language: German
- Year: 2016
- Author: LaSala Michael C
- Language: English
- Year: 2010
- Author: Atkinson Meera
- Language: English
- Year: 2019