@article{DAN_1996_350_1_a3,
     author = {E. S. Levitin},
     title = {On a distance estimate and the form of a tangent cone to the graph},
     journal = {Doklady Akademii Nauk},
     pages = {14--18},
     publisher = {mathdoc},
     volume = {350},
     number = {1},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1996_350_1_a3/}
}