@article{PFMT_2010_4_a3,
     author = {A. V. Gavriliouk and A. A. Gavriluk},
     title = {The problem of definition of derivative without invoking the concept of limit},
     journal = {Problemy fiziki, matematiki i tehniki},
     pages = {24--28},
     publisher = {mathdoc},
     number = {4},
     year = {2010},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PFMT_2010_4_a3/}
}