@article{DAN_1977_235_6_a7,
     author = {A. D. Mednykh},
     title = {On branched coverings of {Riemann} surfaces with the trivial group of covering transformations},
     journal = {Doklady Akademii Nauk},
     pages = {1267--1269},
     publisher = {mathdoc},
     volume = {235},
     number = {6},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1977_235_6_a7/}
}