Actually I really hate the politics on the Spiegel-Gutenberg page not to allow a complete download. So it's good to find at gutenberg.net at least some very interesting things in German. E.g. the complete history of Rome from Mommsen.
A. Hotho, R. Jäschke, C. Schmitz, and G. Stumme. Proceedings of the First Conceptual Structures Tool Interoperability Workshop at the 14th International Conference on Conceptual Structures, page 87-102. Aalborg, Aalborg Universitetsforlag, (2006)