@article{MZM_1994_56_6_a14,
     author = {V. A. Krasnov},
     title = {Two-sheeted coverings of real algebraic surfaces},
     journal = {Matemati\v{c}eskie zametki},
     pages = {137--140},
     publisher = {mathdoc},
     volume = {56},
     number = {6},
     year = {1994},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1994_56_6_a14/}
}