@article{DAN_1987_293_3_a6,
     author = {Yu. A. Skoblin},
     title = {On the class of {Sturm--Liouville} operators on a semiaxis,
},
     journal = {Doklady Akademii Nauk},
     pages = {541--544},
     publisher = {mathdoc},
     volume = {293},
     number = {3},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1987_293_3_a6/}
}