Primitive Words and Languages Associated to PCP. - Marjo Lipponen (Bull. EATCS, 1994)

On F-Prime Solutions of the Post Correspondence Problem. - Marjo Lipponen (Developments in Language Theory, 1995)

Post Correspondence Problem: Words Possible as Primitive Solutions. - Marjo Lipponen (ICALP, 1995)

Strongly Prime PCP Words. - Marjo Lipponen; Gheorghe Paun (Discret. Appl. Math., 1995)

Simple Words in Equality Sets. - Marjo Lipponen; Arto Salomaa (Bull. EATCS, 1996)

Flatwords and Post Correspondence Problem. - Tero Harju; Marjo Lipponen; Alexandru Mateescu (Theor. Comput. Sci., 1996)

Minimal Deterministic Incomplete Automata. - Elena Calude; Marjo Lipponen (J. Univers. Comput. Sci., 1997)

Computational Complementarity and Sofic Shifts. - Cristian S. Calude; Marjo Lipponen (CATS, 1998)

Distinguishability, Simulation and Universality of Moore Tree Automata. - Eija Jurvanen; Marjo Lipponen (Fundam. Informaticae, 1999)

Computational Complementarity and Shift Spaces. - Marjo Lipponen (J. Univers. Comput. Sci., 2000)

Simple Words in Equality Sets. - Marjo Lipponen; Arto Salomaa (Current Trends in Theoretical Computer Science, 2001)