Hans-Peter Kriegel, Hermann A. Maurer. Formal translations and the containment problem for Szilard languages. In H. Barkhage, editor, Automata Theory and Formal Languages, 2nd GI Conference, Kaiserslautern, May 20-23, 1975. Volume 33 of Lecture Notes in Computer Science, pages 233-238, Springer, 1975.
Abstract is missing.