Information System Concepts: An Integrated Discipline Emerging : IFIP TC8/WG8.1 International Conference on Information System Concepts: An Integrated Discipline Emerging (ISCO-4)September 20.22, 1999, University of Leiden, The Netherlands - Eckhard D. Falkenberg, Kalle Lyytinen, Alexander A. Verrijn-Stuart ((IFIP Advances in Information and Communication Technology))