1. Buettner, W., "Unification in the datastructure multiset", Journal of Automated Reasoning, vol.2, pp. 75–88, (1986).
2. Buettner,W., "Unification in the datastructure set", (to appear in this Proc. of 8th CADE)
3. Cunningham, R.J., Dick, A.J.J., "Rewrite Systems on a Lattice of Types", Rep. No. DOC 83/7, Imperial College, London SW7 (1983)
4. Cohn, A.G. "Improving the Expressiveness of Many-sorted Logic.", AAAI-83, Washington (1983)
5. Fages, F. "Formes canonique dans les algèbres booleènnes et application à la dèmonstration automatique en logique de premier ordre." Thèse du 3eme cycle, Paris, (1983)