@article{DAN_1957_116_6_a4,
     author = {A. A. Markov},
     title = {On the inversion complexity of function systems},
     journal = {Doklady Akademii Nauk},
     pages = {917--919},
     publisher = {mathdoc},
     volume = {116},
     number = {6},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_116_6_a4/}
}