@article{IM2_2018_82_2_a4,
     author = {A. M. Savchuk},
     title = {On the basis property of the system of eigenfunctions and associated functions
},
     journal = {Izvestiya. Mathematics },
     pages = {351--376},
     publisher = {mathdoc},
     volume = {82},
     number = {2},
     year = {2018},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2018_82_2_a4/}
}