@article{DAN_1985_280_1_a7,
     author = {V. A. Lyubetskii},
     title = {Some algebraic questions of nonstandard analysis},
     journal = {Doklady Akademii Nauk},
     pages = {38--41},
     publisher = {mathdoc},
     volume = {280},
     number = {1},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1985_280_1_a7/}
}