@article{RM_1976_31_5_a25,
     author = {V. A. Efremovich and Yu. B. Rudyak},
     title = {On the concept of the {Euler} characteristic},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {31},
     number = {5},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1976_31_5_a25/}
}