@article{EMJ_2021_12_1_a6,
     author = {B. Zh. Omarova and Zh. A. Sartabanov},
     title = {On multiperiodic solutions of perturbed nonlinear autonomous systems with the differentiation operator on a vector field},
     journal = {Eurasian mathematical journal},
     pages = {68--81},
     publisher = {mathdoc},
     volume = {12},
     number = {1},
     year = {2021},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EMJ_2021_12_1_a6/}
}