1. Blum, M., Hewitt, C.: Automata on a 2-dimensional tape. In: Proc. IEEE Computer Society, SWAT 1967, Washington, DC, USA, pp. 155–160 (1967)
2. Borchert, B., Reinhardt, K.: Deterministically and sudoku-deterministically recognizable picture languages. In: Loos, R., Fazekas, S., Martin-Vide, C. (eds.) LATA 2007, Preproc. Report 35/07. Research Group on Mathematical Linguistics, pp. 175–186. Universitat Rovira i Virgili, Tarragona (2007)
3. Giammarresi, D., Restivo, A.: Two-dimensional languages. In: Rozenberg, G., Salomaa, A. (eds.) Handbook of Formal Languages, vol. 3, pp. 215–267. Springer, New York (1997)
4. Hennie, F.: One-tape, off-line Turing machine computations. Inform. Contr. 8, 553–578 (1965)
5. Lecture Notes in Computer Science;P. Jančar,1995