@article{DAN_1981_257_4_a13,
     author = {L. Ya. Savel'ev},
     title = {Extension of outer measures},
     journal = {Doklady Akademii Nauk},
     pages = {830--833},
     year = {1981},
     volume = {257},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1981_257_4_a13/}
}