@article{MZM_2021_109_1_a1,
     author = {A. Kh. Askarova and V. \`E. Ismailov},
     title = {A {Chebyshev-Type} {Theorem} {Characterizing} {Best} {Approximation} of a {Continuous} {Function} by {Elements} of the {Sum} of {Two} {Algebras}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {19--26},
     publisher = {mathdoc},
     volume = {109},
     number = {1},
     year = {2021},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2021_109_1_a1/}
}