@article{AL_2022_61_1_a2,
     author = {B. S. Kalmurzaev and N. A. Bazhenov and M. A. Torebekova},
     title = {Index sets for classes of positive preorders},
     journal = {Algebra i logika},
     pages = {42--76},
     publisher = {mathdoc},
     volume = {61},
     number = {1},
     year = {2022},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2022_61_1_a2/}
}