@article{DAN_1965_164_3_a1,
     author = {Z. Hedrl{\'\i}n},
     title = {Commutative systems as generalized semigroups},
     journal = {Doklady Akademii Nauk},
     pages = {483--486},
     publisher = {mathdoc},
     volume = {164},
     number = {3},
     year = {1965},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1965_164_3_a1/}
}