@article{DAN_1968_180_4_a8,
     author = {R. V. Freivald},
     title = {The completeness to within coding of systems of functions of a $k$-valued logic and the complexity of its recognition},
     journal = {Doklady Akademii Nauk},
     pages = {803--805},
     publisher = {mathdoc},
     volume = {180},
     number = {4},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_180_4_a8/}
}