@article{DAN_1970_190_3_a3,
     author = {Yu. N. Bibikov},
     title = {The stability of periodic motions in the transcendental case of two pure imaginary characteristic exponents},
     journal = {Doklady Akademii Nauk},
     pages = {506--509},
     publisher = {mathdoc},
     volume = {190},
     number = {3},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_190_3_a3/}
}