@article{DAN_1995_344_2_a7,
     author = {A. B. Petrovskii},
     title = {Metric spaces of multisets},
     journal = {Doklady Akademii Nauk},
     pages = {175--177},
     publisher = {mathdoc},
     volume = {344},
     number = {2},
     year = {1995},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1995_344_2_a7/}
}