1. Trace theory — a survey;Aalbersberg,1985
2. Trace languages defined by regular string languages;Aalbersberg,1984
3. An application of the theory of free partially commutative monoids: asymptotic densities of trace languages;Bertoni,1981
4. A characterization of context-free string languages by directed node-label controlled graph grammars;Janssens,1981
5. Semigroups and Combinatorial Applications;Lallement,1979