@article{AL_1972_11_2_a1,
     author = {A. N. Degtev},
     title = {The $m$-degrees of simple sets},
     journal = {Algebra i logika},
     pages = {130--139},
     publisher = {mathdoc},
     volume = {11},
     number = {2},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1972_11_2_a1/}
}