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2. H.-J. Bürckert: Lazy Theory Unification in PROLOG: An Extension of the Warren Abstract Machine. Proc. of 10th German Workshop on Art. Intelligence, Springer, 1986, p. 277–288.
3. H.-J. Bürckert: Matching — A Special Case of Unification? SEKI-Report, Universität Kaiserslautern, 1987.
4. H.-J. Bürckert: Solving Disequations in Equational Theories. SEKI-Report, Universität Kaiserslautern, 1987.
5. H.-J. Bürckert, A. Herold & M. Schmidt-Schauß: On Equational Theories, Unification, and Decidability. Proc. of 2nd Conf. on Rewriting Techniques and Applications, Springer, LNCS 256, 1987, p. 204–215; to appear also in J. of Symb. Comp., Special Issue on Unification (ed. C. Kirchner), 1987.