G. Stumme. Data Analysis and Information Systems. Statistical and Conceptual approaches. Proc. GfKl'95. Studies in Classification, Data Analysis, and Knowledge Organization 7, page 457-469. Heidelberg, Springer, (1996)
G. Stumme. Ordinal and Symbolic Data Analysis. Proc. OSDA'95. Studies in Classification, Data Analysis, and Knowledge Organization 8, page 31-44. Heidelberg, Springer, (1996)