@article{MZM_1980_27_5_a12,
     author = {Yu. A. Ignatov},
     title = {Roots of unity as nonfree points of the complex plane},
     journal = {Matemati\v{c}eskie zametki},
     pages = {825--827},
     publisher = {mathdoc},
     volume = {27},
     number = {5},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1980_27_5_a12/}
}