@article{DAN_1993_333_6_a4,
     author = {A. I. Subbotin and N. N. Subbotina},
     title = {Piecewise-smooth solutions of first-order partial differential},
     journal = {Doklady Akademii Nauk},
     pages = {705--707},
     publisher = {mathdoc},
     volume = {333},
     number = {6},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1993_333_6_a4/}
}