@article{UZKU_2016_158_1_a3,
     author = {D. Kh. Zainetdinov},
     title = {$\Sigma$-reducibility and $lm$-reducibility of sets and sequences of sets},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {51--65},
     publisher = {mathdoc},
     volume = {158},
     number = {1},
     year = {2016},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZKU_2016_158_1_a3/}
}