- document
- Wittenberg, H. (author), Spies, G.J. (author) report 1949
- document
- Wittenberg, H. (author), Spies, G.J. (author) report 1948
- document
- Wittenberg, H. (author), Spies, G.J. (author) report 1948
- document
- Wittenberg, H. (author), Spies, G.J. (author) report 1947
- document
- Wittenberg, H. (author), Spies, G.J. (author) report 1947
- document
- Wittenberg, H. (author), Spies, G.J. (author) report 1947