@article{TM_1992_198_a1,
     author = {M.-B. Babayev},
     title = {On the order of approximation of {Sobolev} class $W_q^r$ by bilinear forms in $L_p$ for $1\le q\le2\le p\le\infty$},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {21--40},
     publisher = {mathdoc},
     volume = {198},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1992_198_a1/}
}