@article{DAN_1991_317_3_a7,
     author = {I. S. Zakharevich},
     title = {Spectral problems for the {Sturm--Liouville} equation with a parameter. {The} geometry of finite-gap potentials},
     journal = {Doklady Akademii Nauk},
     pages = {550--554},
     publisher = {mathdoc},
     volume = {317},
     number = {3},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_317_3_a7/}
}