@article{MZM_1983_34_4_a5,
     author = {R. S. Ismagilov},
     title = {Continuous spectrum of second-order ordinary differential operators},
     journal = {Matemati\v{c}eskie zametki},
     pages = {535--547},
     year = {1983},
     volume = {34},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1983_34_4_a5/}
}