@article{IVM_1980_9_a13,
     author = {P. N. Denisenko},
     title = {A~simple process of numerical differentiation},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {71--73},
     year = {1980},
     number = {9},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1980_9_a13/}
}