\Bibitem{VerPav87} \by V.~V.~Vershinin, N.~N.~Pavlov \paper Splines in a convex set and the problem of numerical differentiation \jour Zh. Vychisl. Mat. Mat. Fiz. \yr 1987 \vol 27 \issue 4 \pages 621--626 \mathnet{http://mi.mathnet.ru/zvmmf3849} \mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=889888} \zmath{https://zbmath.org/?q=an:0623.65007} \transl \jour U.S.S.R. Comput. Math. Math. Phys. \yr 1987 \vol 27 \issue 2 \pages 199--202 \crossref{https://doi.org/10.1016/0041-5553(87)90178-9}