S. A. Puzynina, Sergey V. Avgustinovich. On periodicity of two-dimensional words. Theoretical Computer Science, 391(1-2):178-187, 2008. [doi]
@article{PuzyninaA08,
title = {On periodicity of two-dimensional words},
author = {S. A. Puzynina and Sergey V. Avgustinovich},
year = {2008},
doi = {10.1016/j.tcs.2007.10.038},
url = {http://dx.doi.org/10.1016/j.tcs.2007.10.038},
researchr = {https://researchr.org/publication/PuzyninaA08},
cites = {0},
citedby = {0},
journal = {Theoretical Computer Science},
volume = {391},
number = {1-2},
pages = {178-187},
}