1. Unification in the datastructure multisets;Bütter,1985
2. Aldes and SAC-2 now available;Collins;SIGSAM Bull.,1980
3. Associative-commutative unification;Fages,1984
4. Algebraische Unifikation;Fortenbacher,1983
5. Unification under associativity and commutativity;Fortenbacher,1985