@article{MO_2014_4_a0,
     author = {V. Drozdov},
     title = {Five circles},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {2--5},
     year = {2014},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_2014_4_a0/}
}