@article{DAN_1958_118_2_a7,
     author = {Ya. L. Kreinin},
     title = {About a property of sets effectively different from all $\Phi$-sets},
     journal = {Doklady Akademii Nauk},
     pages = {237--238},
     publisher = {mathdoc},
     volume = {118},
     number = {2},
     year = {1958},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_118_2_a7/}
}