@article{INTO_1999_61_a0,
     author = {S. I. Dudov},
     title = {On the generalized gradient of the distance function},
     journal = {Itogi nauki i tehniki. Sovremenna\^a matematika i e\"e prilo\v{z}eni\^a. Temati\v{c}eskie obzory},
     pages = {5--14},
     publisher = {mathdoc},
     volume = {61},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTO_1999_61_a0/}
}