@article{TDM_2008_11_1_a4,
     author = {V. G. Nikonov and N. V. Nikonov},
     title = {Features of threshold representations of $k$-valued functions},
     journal = {Trudy po diskretnoj matematike},
     pages = {60--85},
     publisher = {mathdoc},
     volume = {11},
     number = {1},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TDM_2008_11_1_a4/}
}