@article{FPM_2020_23_3_a8,
     author = {I. B. Kozhukhov and K. A. Kolesnikova},
     title = {On {Hopfianity} and {co-Hopfianity} of acts over groups},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {131--139},
     publisher = {mathdoc},
     volume = {23},
     number = {3},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_2020_23_3_a8/}
}