@article{TIMM_2012_18_2_a17,
     author = {V. N. Pavlenko and T. A. Petrash},
     title = {Periodic solutions of the vibrating string equation with {Neumann} and {Dirichlet} boundary conditions and a~discontinuous nonlinearity},
     journal = {Trudy Instituta matematiki i mehaniki},
     pages = {199--204},
     year = {2012},
     volume = {18},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TIMM_2012_18_2_a17/}
}