Citation:
A. A. Vasil'eva, “Widths of weighted Sobolev classes on a John domain”, Orthogonal series, approximation theory, and related problems, Collected papers. Dedicated to Academician Boris Sergeevich Kashin on the occasion of his 60th birthday, Trudy Mat. Inst. Steklova, 280, MAIK Nauka/Interperiodica, Moscow, 2013, 97–125; Proc. Steklov Inst. Math., 280 (2013), 91–119