@article{VTPMK_2021_2_a1,
     author = {S. Yu. Graf and I. A. Nikitin},
     title = {Analogs of {S.N.} {Bernstein} and {V.I.} {Smirnov} inequalities for harmonic polynomials},
     journal = {Vestnik Tverskogo gosudarstvennogo universiteta. Seri\^a Prikladna\^a matematika},
     pages = {16--25},
     publisher = {mathdoc},
     number = {2},
     year = {2021},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VTPMK_2021_2_a1/}
}