G. Stumme, and K. Wolff. Advances in Database Technologies. Proc. Intl. Workshop on Data Warehousing and, volume 1552 of LNCS, page 117-128. Heidelberg, Springer, (1999)
M. Skorsky, G. Stumme, R. Wille, and U. Wille. Proc. Workshop on Knowledge Management, Organizational Memory and Reuse, 5th German Conf. on, Würzburg, (March 1999)