@article{DAN_1973_210_4_a5,
     author = {Yu. B. Rudyak},
     title = {On the fundamental group of a three-dimensional manifold},
     journal = {Doklady Akademii Nauk},
     pages = {771--774},
     publisher = {mathdoc},
     volume = {210},
     number = {4},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_210_4_a5/}
}