Graphical vs logical specifications, with K.G. Larsen, in Theoretical Computer Science (TCS ) Vol. 106 (1992), 3-20.

This paper studies the relations between two specification formalisms and verification methods for concurrent systems, namely Larsen-Thomsen's modal transition systems -- here called graphical specifications -- and Hennessy-Milner Logic. We show that any graphical specification may be expressed by a logical specification having the same models. Conversely, we give a characterization of the formulae that are graphically representable.