ZUM '98: The Z Formal Specification Notation 11th International Conference of Z Users, Berlin, Germany, September 24-26, 1998, Proceedings - Bowen, Jonathan P.; Bowen, Jonathan P.; Fett, Andreas; Fett, Andreas; Hinchey, Michael G.; Hinchey, Michael G. (Springer Berlin Heidelberg : Imprint: Springer, 1998)