- Author: Rudolf A. Makkreel
- Language: English
- Year: 2022
- Author: Rudolf A. Makkreel
- Language: English
- Year: 2015
- Author: Rudolf A. Makkreel
- Language: English
- Year: 1990
- Author: Rudolf A. Makkreel
- Language: English
- Author: Rudolf A. Makkreel
- Language: English
- Author: Rudolf A. Makkreel
- Language: English
- Year: 2021