@article{ISU_2015_15_4_a3,
     author = {V. P. Kurdyumov},
     title = {On {Riescz} bases of eigenfunction of $2$-nd order differential operator with involution and integral boundary conditions},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {392--405},
     publisher = {mathdoc},
     volume = {15},
     number = {4},
     year = {2015},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ISU_2015_15_4_a3/}
}