- Author: Ulmanis Juris
- Language: English
- Year: 2017
- Author: Ulmanis Juris
- Language: English
- Year: 2017
- Author: Rickles Dean
- Language: English
- Year: 2016
- Author: Rickles Dean
- Language: English
- Year: 2016
- Author: Knünz Valentin
- Language: English
- Year: 2017
- Author: Knünz Valentin
- Language: English
- Year: 2017
- Author: Al-Khalili Jim, McFadden Johnjoe, Vogel Sebastian
- Language: German
- Year: 2015