1985

• On the equivalence of compositions of morphisms and inverse morphisms on regular languages, RAIRO Theoret. Inform. 19 (1985, 203-211 (with H.C.M. Kleijn); preliminary version in Springer Lecture Notes in Computer Science 176, 355-363, 1984. (1)
• Test sets for morphisms with bounded delay. Discrete Appl. Math. 12, 1985, 93-101 (with Ch. Choffrut); preliminary version in Springer Lecture Notes in Computer Science 154, 118-127, 1983. (1)
• A property of three-element codes. Theoret. Comput. Sci. 41 (1985); preliminary version in Springer Lecture Notes in Computer Science 166, 305-313, 1984. (1)
• On three-element codes. Theoret. Comput. Sci. 40 (1985), 3-11; preliminary version in Springer Lecture Notes in Computer Science 172, 292-302, 1984. (1)

1986

• A new proof for the DOL sequence equivalence problem and its implications, in: A. Salomaa and G. Rozenberg (eds.): The Book of L (Springer, 1986) 63-74 (with K. Culik II). (2)
• A simple undecidable problem: Existential agreement of inverses of two morphisms on a regular language. Journal of Computer and System Sciences 32, 315-322, 1986 (with Y. Maon). (1)
• On morphic generation of regular languages. Discrete Appl. Math. 15, 55-60, 1986 (with T. Harju and H.C.M. Kleijn). (1)
• On the defect theorem and simplifiability. Semigroup Forum 33, 199-217, 1986 (with T. Harju) (1)
• A note on the equivalence problem of rational formal power series. Inform. Process. Lett. 23, 29-31, 1986 (with K. Culik II). (1)
• Synchronizable deterministic pushdown automata and the decidability of their equivalence. Acta Informatica 23, 597-605, 1986 (with K. Culik II). (1)
• The equivalence of finite values transducers (on HDTOL languages) is decidable. Theoret. Comput. Sci. 47, 71-84, 1986 (with K. Culik II); preliminary version in Springer Lecture Notes in Computer Science 233, 264-272, 1986. (1)

1987

• The decidability of DTOL sequence equivalence problem and related decision problems, in: H. Laakso and A. Salomaa (eds.): The very knowledge of coding, Studies in honour of Aimo Tietäväinen on the occasion of his fiftieth birthday, 43-54, 1987 (with K. Culik II). (2)
• The equivalence problem for single-valued two-way transducers (on NPDTOL languages) is decidable. SIAM J. Comp. 16, 221-230, 1987 (with K. Culik II). (1)
• The Ehrenfeucht conjecture for transducers. J. Int. Process. Cybern. EIK 23 (1987) 8/9, 389-401. (1)
• Results concerning palindromicity. J. Int. Process. Cybern. EIK 23 (1987) 8/9, 441-451 (with S. Horvath and H.C.M. Kleijn). (1)
• On recent trends in formal language theory. Springer Lecture Notes in Computer Science 267, 136-162, 1987, (invited talk in ICALP 87). (1)

1988

• The equivalence of mappings on languages. Springer Lecture Notes in Computer Science 281, 26-38, 1988. (2)
• Systems of equations over a finitely generated free monoid having an effectively findable equivalent finite subsystem. Springer Lecture Notes in Mathematics 1320, 1988, 18-27 (with K. Culik II). (1)
• On totalistic systolic networks. Inform. Process. Lett. 26 (1987/88), 231-236 (with K. Culik II). (1)

1989

• A note on HTOL languages and the equivalence of deterministic pushdown transducers. Commemorative volume on theoretical computer science - In honour of Gift Siromoney, World Scientific Publ. Company, 1989, 23-32 (with K. Culik II). (2)
• HDTOL-matching of computations of multitape automata. Acta Informatica 27 (1989), 179-191 (with K. Culik II). (1)

1990

• The equivalence problem of multitape finite automata. Theoret. Comput. Sci. 78 (1991), 347-355 (with T. Harju); preliminary version in proceedings of 22nd STOCS, 477-481, 1990. (1)
• Loops in automata and HDTOL relations. RAIRO Theoret. Inform. and Appl. 24 (1990), 327-337 (with K. Culik II); preliminary version in Springer Lecture Notes in Computer Science 349, 468-479, 1989. (1)

1991

• On the power of synchronization in parallel computations. Discrete Appl. Math. 32 (1991), 155-182 (with Anna Slobodova, Juraj Hromkovic and Branislav Rovan); preliminary version in Springer Lecture Notes in Computer Science 379, 196-206, 1989. (1)

1992

• Multiplicities: A deterministic view of nondeterminism. Theoret. Comput. Sci. 98 (1992), 15-25. (1)
• Alternating iteration of morphisms and the Kolakowski sequence, in: Rozenberg, G. and Salomaa,A. (eds.), Lindenmayer Systems, Springer, 1992, 93-106 (with K. Culik II and A. Lepistö). (2)

1993

• Efficient constructions of test sets for regular and context-free languages. Theoret. Comput. Sci. 116 (1993), 305-316 (with W. Rytter and S. Jarominek); preliminary version in Springer Lecture Notes in Computer Science 520, 249-258, 1991. (1)
• Equations over finite sets of words and equivalence problems in automata theory. Theoret. Comput. Sci. 108 (1993), 103-118; preliminary version in: M. Ito (ed.), Words, Languages and Combinatorics, World Scientific, 233-250, 1992. (1)
• The Impact of DOL Problem, in G. Rozenberg and A. Salomaa (eds.), Trends in Theoretical Computer Science, World Scientific, 586-594, 1993. (2)