1. Efficient detection of quasiperiodicities in strings;Apostolico;Theoret. Comput. Sci.,1993
2. Fractals Everywhere;Barnsley,1988
3. Automata on two-dimensional tape;Blum,1967
4. Two-dimensional languages;Giammarresi,1997
5. Collage grammars;Habel,1991