@article{MZM_2010_87_6_a6,
     author = {M. Yu. Maksimovskiy},
     title = {Bipolygons and {Multipolygons} over {Semigroups}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {855--866},
     publisher = {mathdoc},
     volume = {87},
     number = {6},
     year = {2010},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2010_87_6_a6/}
}