@article{DAN_1967_173_3_a11,
     author = {G. N. Tyurina},
     title = {On a type of contractible curves},
     journal = {Doklady Akademii Nauk},
     pages = {529--531},
     publisher = {mathdoc},
     volume = {173},
     number = {3},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_173_3_a11/}
}