@article{CMFD_2007_21_a1,
     author = {N. B. Zhuravlev},
     title = {Hyperbolicity criterion for periodic solutions of functional-differential equations with several delays},
     journal = {Contemporary Mathematics. Fundamental Directions},
     pages = {37--61},
     publisher = {mathdoc},
     volume = {21},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/CMFD_2007_21_a1/}
}