@article{MZM_2001_69_2_a15,
     author = {E. V. Zhuzhoma and V. S. Medvedev},
     title = {The {Closure} {Lemma} for {Piecewise} {Diffeomorphic} {Maps} of the {Circle}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {310--313},
     publisher = {mathdoc},
     volume = {69},
     number = {2},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2001_69_2_a15/}
}