@article{TRSPY_2012_278_a8,
     author = {E. V. Zhuzhoma and N. V. Isaenkova},
     title = {Classification of coverings of the circle},
     journal = {Informatics and Automation},
     pages = {96--101},
     year = {2012},
     volume = {278},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_2012_278_a8/}
}