@article{ZVMMF_2009_49_4_a4,
     author = {A. A. Abramov and V. I. Ul'yanova and L. F. Yukhno},
     title = {General nonlinear self-adjoint eigenvalue problem for systems of ordinary differential equations},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {624--627},
     publisher = {mathdoc},
     volume = {49},
     number = {4},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_2009_49_4_a4/}
}