On the darboux transformation of second order ordinary differential operator
1988 ◽
Vol 64
(9)
◽
pp. 327-330
1978 ◽
Vol 82
(1-2)
◽
pp. 117-134
◽
Basis property of a system of eigenfunctions of a second-order differential operator with involution
2019 ◽
Vol 29
(2)
◽
pp. 183-196