@article{DAN_1971_201_4_a8,
     author = {M. F. Ra\c{t}\u{a}},
     title = {A criterion for functional completeness in the intuitionistic propositional logic},
     journal = {Doklady Akademii Nauk},
     pages = {794--797},
     publisher = {mathdoc},
     volume = {201},
     number = {4},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_201_4_a8/}
}