@article{SM_1980_37_3_a7,
     author = {V. I. Ruderfer},
     title = {On the zeros of solutions of a~linear analytic partial differential equation of arbitrary order},
     journal = {Sbornik. Mathematics},
     pages = {403--410},
     publisher = {mathdoc},
     volume = {37},
     number = {3},
     year = {1980},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1980_37_3_a7/}
}