@article{IVM_1978_9_a11,
     author = {R. Sh. Omanadze},
     title = {Some generalizations of the concept of productivity of a~set},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {84--88},
     publisher = {mathdoc},
     number = {9},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1978_9_a11/}
}