[Hereth et al. 2000] Hereth, J., Stumme, G., Wille, R. and Wille, U.: "Conceptual Knowledge Discovery and Data Analysis" Ganter, B. and Mineau, G. W., eds.; Conceptual Structures: Logical, Linguistic, and Computational  Issues. Proc. ICCS '00, Springer, Heidelberg (2000), 421-437.