@article{MZM_2019_106_3_a5,
     author = {K. D. Kovalenko and A. M. Raigorodskii},
     title = {Systems of {Representatives}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {387--394},
     publisher = {mathdoc},
     volume = {106},
     number = {3},
     year = {2019},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2019_106_3_a5/}
}