@article{SM_1972_18_3_a4,
     author = {Z. I. Leibenzon},
     title = {Algebraic-differential transformations of linear differential operators of arbitrary order and their spectral properties applicable to the inverse problem},
     journal = {Sbornik. Mathematics},
     pages = {425--471},
     publisher = {mathdoc},
     volume = {18},
     number = {3},
     year = {1972},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1972_18_3_a4/}
}