@article{MT_2004_7_1_a5,
     author = {A. I. Parfenov},
     title = {The {\'Curgus} {Condition} in {Indefinite} {Sturm{\textendash}Liouville} {Problems}},
     journal = {Matemati\v{c}eskie trudy},
     pages = {153--188},
     year = {2004},
     volume = {7},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_2004_7_1_a5/}
}