@article{MZM_1989_46_3_a13,
     author = {Yu. A. Shashkin},
     title = {Euler characteristic and multiple coverings},
     journal = {Matemati\v{c}eskie zametki},
     pages = {110--113},
     publisher = {mathdoc},
     volume = {46},
     number = {3},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1989_46_3_a13/}
}