@article{MZM_1970_8_2_a8,
     author = {L. A. Bunimovich},
     title = {A transformation of the circle},
     journal = {Matemati\v{c}eskie zametki},
     pages = {205--216},
     publisher = {mathdoc},
     volume = {8},
     number = {2},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1970_8_2_a8/}
}