\Bibitem{LinBor26} \by Yu.~Yu.~Linke, I.~S.~Borisov \paper Approximation of smooth regression functions of multiple variables by universal kernel estimators \jour Teor. Veroyatnost. i Primenen. \yr 2026 \vol 71 \issue 1 \pages 3--17 \mathnet{http://mi.mathnet.ru/tvp5797} \crossref{https://doi.org/10.4213/tvp5797}