@article{DAN_1966_171_4_a5,
     author = {S. L. Krushkal'},
     title = {On the theory of extremal problems for quasi-conformal mappings of closed {Riemann} surfaces},
     journal = {Doklady Akademii Nauk},
     pages = {784--787},
     publisher = {mathdoc},
     volume = {171},
     number = {4},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1966_171_4_a5/}
}