On the degree of approximation of the Sobolev class $W_q^r$ by bilinear forms in $L_p$ for $1\leqslant q\leqslant p\leqslant 2$

The degree of best approximation by bilinear forms in $L_p$, where $1\leqslant q\leqslant p\leqslant 2$, is established for the class $W_q^r$.