@article{MO_2017_83_3_a1,
     author = {T. N. Bryantseva and V. A. Delyanov},
     title = {Differentiation of functions at the secondary school},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {7--12},
     publisher = {mathdoc},
     volume = {83},
     number = {3},
     year = {2017},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_2017_83_3_a1/}
}