Hard Sets Method and Semilinear Reservoir Method with Applications. - Leonid P. Lisovik (ICALP, 1996)

Nondeterministic systems and finite substitutions on regular languages. - Leonid P. Lisovik (Bull. EATCS, 1997)

On the Equivalence of Finite Substitutions and Transducers. - Juhani Karhumäki; Leonid P. Lisovik (Jewels are Forever, 1999)

A Simple Undecidable Problem: The Inclusion Problem for Finite Substitutions on ab*c. - Juhani Karhumäki; Leonid P. Lisovik (STACS, 2001)

The Equivalence Problem of Finite Substitutions on ab*c, with Applications. - Juhani Karhumäki; Leonid P. Lisovik (ICALP, 2002)

A simple undecidable problem: the inclusion problem for finite substitutions on ab*c. - Juhani Karhumäki; Leonid P. Lisovik (Inf. Comput., 2003)

The Equivalence Problem of Finite Substitutions on ab*c, with Applications. - Juhani Karhumäki; Leonid P. Lisovik (Int. J. Found. Comput. Sci., 2003)