@article{AL_2017_56_4_a3,
     author = {Yu. L. Ershov},
     title = {Solimit points and $u$-extensions},
     journal = {Algebra i logika},
     pages = {443--452},
     publisher = {mathdoc},
     volume = {56},
     number = {4},
     year = {2017},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2017_56_4_a3/}
}