@article{DAN_1960_133_4_a5,
     author = {V. I. Gaǐduk},
     title = {On nonlinear oscillations in a weak external field, a description by {Lagrange's} equations},
     journal = {Doklady Akademii Nauk},
     pages = {760--763},
     publisher = {mathdoc},
     volume = {133},
     number = {4},
     year = {1960},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_133_4_a5/}
}