@article{MMO_2014_75_2_a11,
     author = {K. A. Mirzoev},
     title = {Sturm--Liouville operators},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {335--359},
     publisher = {mathdoc},
     volume = {75},
     number = {2},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_2014_75_2_a11/}
}