@article{SEMR_2011_8_a16,
     author = {D. V. Solomatin},
     title = {Semigroups with outerplanar {Cayley} graphs},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {191--212},
     publisher = {mathdoc},
     volume = {8},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2011_8_a16/}
}