@article{DAN_1988_300_4_a11,
     author = {A. E. Fryntov},
     title = {An extremal problem of potential theory},
     journal = {Doklady Akademii Nauk},
     pages = {819--820},
     publisher = {mathdoc},
     volume = {300},
     number = {4},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1988_300_4_a11/}
}