@article{TRSPY_1987_180_a44,
     author = {Yu. I. Volkov},
     title = {On approximation in the mean by multidimensional positive linear operators},
     journal = {Informatics and Automation},
     pages = {85--86},
     publisher = {mathdoc},
     volume = {180},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1987_180_a44/}
}