COOPN/2 (Concurrent Object Oriented Petri Nets) is an object-oriented specification formalism based on Petri Nets and algebraic specifications. It is fully adapted to the specification of complex concurrent systems because it inherits the advantages of algebraic specifications for the specification of abstract data types, from Petri nets to describe partially ordered events and from the object-oriented paradigm for the 'structuring' of the specification. All these features are especially useful when speaking about groupware systems, which are application which demand rich modeling capabilities on concurrency and structuring. This paper explains the major principles for the specification of groupware systems with COOPN/2. This is done by mapping groupware concepts into COOPN/2 concepts and is demonstrated by means of an example of shared distributed diaries. Furthermore, we present the work done on the methodological approach for the development of concurrent object-oriented systems with COOPN/2 which cover analysis, specification, design, prototyping and testing. groupware, replication, object-orientation, distributed systems, formal methods, Petri Nets, algebraic specification of abstract data types, software engineering.<p> Keywords : groupware, replication, object-orientation, distributed systems, formal methods, Petri Nets, algebraic specification of abstract data types, software engineering.