@article{DAN_1967_176_5_a13,
     author = {A. M. Stepin},
     title = {Square roots of metric automorphisms},
     journal = {Doklady Akademii Nauk},
     pages = {1023--1026},
     publisher = {mathdoc},
     volume = {176},
     number = {5},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_176_5_a13/}
}