- Author: Prof. Don Edward Beck, Teddy Hebo Larsen, Sergey Solonin, Dr. Rica Viljoen, Thomas Q. Johns
- Language: English
- Year: 2018
- Author: Nico Martins, Ellen Caroline Martins, Rica Viljoen
- Language: English
- Year: 2017
- Author: Russel Viljoen
- Language: English
- Year: 2022
- Author: Wilhelm Jacob Viljoen
- Language: German
- Year: 1896
- Author: Poonam Bala (editor) Russel Viljoen (editor)
- Language: English
- Year: 2023
- Author: Ben J. (Ben Johannis) Viljoen
- Language: English
- Year: 1973
- Author: Russel Viljoen
- Language: English
- Year: 2022
