@article{IVM_1977_4_a14,
     author = {A. Ya. Ovsyannikov},
     title = {Structural isomorphisms of commutative semigroups with one defining relation},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {136--138},
     publisher = {mathdoc},
     number = {4},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1977_4_a14/}
}