@article{VMUMM_1989_3_a16,
     author = {S. A. Logunov and V. I. Malykhin},
     title = {Nowhere dense subsets of $N^*$ and types of ultrafilters},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {59--61},
     publisher = {mathdoc},
     number = {3},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1989_3_a16/}
}