@article{MZM_1989_46_1_a16,
     author = {D. N. Cheban},
     title = {A problem of {J.~Hale}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {120--121},
     publisher = {mathdoc},
     volume = {46},
     number = {1},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1989_46_1_a16/}
}