1. Res. Rept. CS-81-32;K. Culik II,1981
2. Culik II, K., Gruska, J., Salomaa, A.: Systolic trellis automata (for VLSI). Ibid., CS-81-34
3. Culik II, K., Gruska, J., Salomaa, A.: On a family of L languages resulting from systolic tree automata. Ibid., CS-81-36
4. Culik II, K., Gruska, J., Salomaa, A.: On nonregular context-free languages and pumping. EATCS Bulletin 16, 22–24 (1982)