@article{PDM_2009_2_a4,
     author = {N. G. Parvatov},
     title = {Completeness problems for descrete functions},
     journal = {Prikladna\^a diskretna\^a matematika},
     pages = {56--78},
     publisher = {mathdoc},
     number = {2},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PDM_2009_2_a4/}
}