@article{DAN_1975_221_3_a9,
     author = {O. B. Sidonskii},
     title = {On dual operators on a group},
     journal = {Doklady Akademii Nauk},
     pages = {547--550},
     publisher = {mathdoc},
     volume = {221},
     number = {3},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_221_3_a9/}
}