I: Addresses and Talks Given at the Colloquium -- Congratulatory Address -- Congratulatory Address -- Congratulatory Address -- Congratulatory Address -- Congratulatory Address -- Carl Adam Petri and Informatics -- Applying Petri Net Based Models in the Design of Systems -- II: Contributed Papers -- Some Classes of Live and Safe Petri Nets -- A Model of Cooperation and its Specification with Nets -- The Communication Disciplines of CHAOS -- On the Structure of Dependence Graphs -- Some Remarks on D-continuity -- Numerical Simulations with Place/Transactor-Nets -- Net Models of Dynamically Evolving Data Structures -- On Condition/Event Representations of Place/Transition Nets -- Finite Conjunctive Nondeterminism -- Petri Net Languages and One-Sided Dyck-Reductions on Context- Free Sets -- From Nets to Logic and back in the Specification of Processes -- Types and Modules for Net Specifications -- An Introduction to the Macro COSY Notation -- Linear Algebraic Calculation of Deadlocks and Traps -- On Different Kinds of Frozen Tokens in Petri Nets -- High Level Petri Nets and Distributed Termination -- Communication and Database Oriented Modelling of Multilateral Cooperation - A Comparison Based on Petri Nets -- The Structure of Facts in Occurrence Nets -- Observing Net Behaviour -- Algebraic Models of Parallelism and Net Theory -- Towards a Synchrony Theory for P/T Nets -- The Semantics of a Net is a Net - An Exercise in General Net Theory -- On the Mutual Simulat ability of Different Types of Petri Nets -- Development and Application of Petri Net based Techniques in Australia -- Quantitative Analysis of a Resource Allocation Problem: A Net Theory Based Proposal -- Existential Quantifiers in Predicate-Fact-Nets -- Petri Nets for Sequence Constraint Propagation in Knowledge Based Approaches -- Extension and Intension of Actions -- Interface as a Basic Concept for Systems Specification and Verification -- Specification and Verification of Asynchronous Circuits using Marked Graphs.