@article{VKAM_2019_26_1_a0,
     author = {A. P. Goryushkin},
     title = {Double cosets in free product},
     journal = {Vestnik KRAUNC. Fiziko-matemati\v{c}eskie nauki},
     pages = {8--16},
     publisher = {mathdoc},
     volume = {26},
     number = {1},
     year = {2019},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VKAM_2019_26_1_a0/}
}