E. V. Shishkova, “Exact orders of errors in smooth functions approximations”, Izv. Saratov Univ. Math. Mech. Inform., 6:1-2 (2006), 45–57
2.
G. V. Khromova, E. V. Shishkova, “Constructing regularization methods in the spaces of differentiable functions”, Zh. Vychisl. Mat. Mat. Fiz., 46:11 (2006), 1915–1922; Comput. Math. Math. Phys., 46:11 (2006), 1827–1834
