@article{DAN_1964_157_1_a7,
     author = {I. S. Kac},
     title = {Behaviour of spectral functions of differential systems with boundary conditions at a singular endpoint},
     journal = {Doklady Akademii Nauk},
     pages = {34--37},
     publisher = {mathdoc},
     volume = {157},
     number = {1},
     year = {1964},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1964_157_1_a7/}
}