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@article{MZM_1992_51_2_a22, author = {V. V. Ryzhikov}, title = {An estimate of the entropy of a class of $Z^2$-actions}, journal = {Matemati\v{c}eskie zametki}, pages = {152--155}, publisher = {mathdoc}, volume = {51}, number = {2}, year = {1992}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1992_51_2_a22/} }
V. V. Ryzhikov. An estimate of the entropy of a class of $Z^2$-actions. Matematičeskie zametki, Tome 51 (1992) no. 2, pp. 152-155. http://geodesic.mathdoc.fr/item/MZM_1992_51_2_a22/