A New Proof for Undecidability of the Bi-Infinite Post Correspondence Problem. - Vesa Halava; Tero Harju; Esa Sahla (Fundam. Informaticae, 2017)

On fixed points of rational transductions. - Vesa Halava; Tero Harju; Esa Sahla (Theor. Comput. Sci., 2018)

On Shuffling a Word with its Letter-to-Letter Substitution. - Vesa Halava; Tero Harju; Esa Sahla (Fundam. Informaticae, 2020)

The Conjugate Post Correspondence Problem. - Vesa Halava; Tero Harju; Esa Sahla (CoRR, 2021)

On bi-infinite and conjugate post correspondence problems. - Olivier Finkel; Vesa Halava; Tero Harju; Esa Sahla (RAIRO Theor. Informatics Appl., 2023)

Decision Problems on Copying and Shuffling. - Vesa Halava; Tero Harju; Dirk Nowotka; Esa Sahla (Fundam. Informaticae, 2024)