@article{ISU_2013_13_4_a23,
     author = {A. R. Khaliullina},
     title = {Congruences of acts over groups},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {133--137},
     publisher = {mathdoc},
     volume = {13},
     number = {4},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ISU_2013_13_4_a23/}
}