@article{IVM_1984_4_a19,
     author = {Ya. L. Shapiro and V. A. Igoshin and E. I. Yakovlev},
     title = {Morphisms of second order and second-order differential equations},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {80--82},
     publisher = {mathdoc},
     number = {4},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1984_4_a19/}
}