1. Financial laws as algebraic automata;International Journal of Intelligent Systems;2001-07-30
2. Rational Generating Functions;Enumerative Combinatorics;1986
3. Grammatical Families of Languages;North-Holland Mathematical Library;1986
4. Further Applications of Semigroups;Undergraduate Texts in Mathematics;1984
5. Differentiably Finite Power Series;European Journal of Combinatorics;1980-06