@article{TM_1980_145_a2,
     author = {V. N. Gabushin},
     title = {Optimal methods for calculating values of the operator $Ux$ if $x$~is given with an error. {Differentiation} of functions defined with an error},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {63--78},
     publisher = {mathdoc},
     volume = {145},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1980_145_a2/}
}