@article{ZVMMF_1999_39_4_a6,
     author = {A. G. Nikitin},
     title = {On the principal eigenfunction of a singularly perturbed {Sturm{\textendash}Liouville} problem},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {588--591},
     publisher = {mathdoc},
     volume = {39},
     number = {4},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1999_39_4_a6/}
}