Minimalizations of NFA Using the Universal Automaton, CIAA 2004, poster

Minimalizations of NFA Using the Universal Automaton, DCFS 2004, pdf

On pseudovarieties of semiring homomorphisms, MFCS 2004, pdf

Algebraic theory of regular languages, an amalgam of my presentations at DCFS 2004, MFCS 2004 and at Summer School on General Algebra and Ordered Sets, Czech Republic, 2004, pdf

Algebraic theory of regular languages, slides made from the presentation above, ps

Slides

On equational logic (for semigroups) (1998)

Unification in certain varieties of unary semigroups
(1999)