@article{RLINA_1977_8_63_5_a13,
     author = {Ladde, G.S.},
     title = {Oscillations caused by retarded perturbations of first order linear ordinary differential equations},
     journal = {Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali},
     pages = {351--359},
     publisher = {mathdoc},
     volume = {Ser. 8, 63},
     number = {5},
     year = {1977},
     zbl = {0402.34058},
     mrnumber = {0548601},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RLINA_1977_8_63_5_a13/}
}