@article{SM_1976_30_4_a6,
     author = {A. V. Babin},
     title = {A~formula expressing the solution of a~differential equation with analytic coefficients on a~manifold without boundary in terms of the data of the problem},
     journal = {Sbornik. Mathematics},
     pages = {539--563},
     year = {1976},
     volume = {30},
     number = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1976_30_4_a6/}
}