@article{PDM_2012_2_a0,
     author = {S. N. Kjazhin and V. M. Fomichev},
     title = {About primitive systems of natural numbers},
     journal = {Prikladna\^a diskretna\^a matematika},
     pages = {5--14},
     publisher = {mathdoc},
     number = {2},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PDM_2012_2_a0/}
}