@article{ISU_2014_14_2_a3,
     author = {M. G. Pleshakov and S. V. Tyshkevich},
     title = {One counterexample of shape-preserving approximation},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {144--150},
     publisher = {mathdoc},
     volume = {14},
     number = {2},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ISU_2014_14_2_a3/}
}