@article{RM_1989_44_1_a4,
     author = {V. M. Tikhomirov},
     title = {A.\,N.~Kolmogorov and approximation theory},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {101--152},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1989},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1989_44_1_a4/}
}