@article{IM2_1977_11_3_a5,
     author = {V. A. Mikhailets},
     title = {Distribution of the eigenvalues of the {Sturm--Liouville} operator equation},
     journal = {Izvestiya. Mathematics },
     pages = {571--582},
     publisher = {mathdoc},
     volume = {11},
     number = {3},
     year = {1977},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1977_11_3_a5/}
}