@article{VMUMM_2001_5_a0,
     author = {A. V. D'yachenko},
     title = {Asymptotic formulas for the eigenvalues of an indefinite {Sturm{\textendash}Liouville} problem with a finite number of turning points},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {3--11},
     year = {2001},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2001_5_a0/}
}