@article{MZM_2002_72_3_a1,
     author = {V. S. Guba},
     title = {Some {Properties} of {Periodic} {Words}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {330--337},
     publisher = {mathdoc},
     volume = {72},
     number = {3},
     year = {2002},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2002_72_3_a1/}
}