@article{DAN_1970_193_6_a9,
     author = {I. D. Stupina},
     title = {Certain properties of $R$- and $R^c$-operations and projective operations, over uncountable systems of sets,},
     journal = {Doklady Akademii Nauk},
     pages = {1248--1250},
     year = {1970},
     volume = {193},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_193_6_a9/}
}