@article{VUU_2014_1_a7,
     author = {A. G. Chentsov},
     title = {Some ultrafilter properties connected with extension constructions},
     journal = {Vestnik Udmurtskogo universiteta. Matematika, mehanika, kompʹ\^uternye nauki},
     pages = {87--101},
     publisher = {mathdoc},
     number = {1},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VUU_2014_1_a7/}
}