@article{DM_2005_17_3_a5,
     author = {S. B. Gashkov and I. B. Gashkov},
     title = {On the complexity of the computation of differentials and gradients},
     journal = {Diskretnaya Matematika},
     pages = {45--67},
     publisher = {mathdoc},
     volume = {17},
     number = {3},
     year = {2005},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_2005_17_3_a5/}
}