@article{RM_1991_46_3_a8,
     author = {V. V. Dubrovskii},
     title = {An abstract {Gel'fand--Levitan} formula},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {217--218},
     publisher = {mathdoc},
     volume = {46},
     number = {3},
     year = {1991},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1991_46_3_a8/}
}