@article{DAN_1988_302_5_a4,
     author = {V. A. Efremovich},
     title = {Qualitative properties of figures},
     journal = {Doklady Akademii Nauk},
     pages = {1048--1050},
     year = {1988},
     volume = {302},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1988_302_5_a4/}
}