1. Picture languages: Tiling systems versus tile rewriting grammars;Cherubini;Theor. Comput. Sci.,2006
2. Local and recognizable hexagonal picture languages;Dersanambika;Int. J. Pattern Recognit. Artif. Intell.,2005
3. S. Ewert, Random context picture grammars: The state of the art’, Manipulation of Graphs, Algebras and Pictures. Essays Dedicated to Hans-J¨org Kreowski on the Occasion of His 60th Birthday, 2009, pp. 135–147.
4. Octagonal picture languages;Ramya;Int. J. Reasoning-Based Intell. Syst.,2017
5. On piecewise testable, starfree, and recognizable picture languages;Matz,1998