@article{MZM_2020_107_6_a4,
     author = {S. M. Gusein-Zade and A.-M. Ya. Raukh},
     title = {On {Simple
}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {855--864},
     publisher = {mathdoc},
     volume = {107},
     number = {6},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2020_107_6_a4/}
}