Asymptotic Methods in the Theory of Linear Differential Equations (S. F. Feshchenko, N. I. Shkil’ and L. D. Nikolenko)
1969 ◽
Vol 8
(4)
◽
pp. 451-491
◽
2019 ◽
Vol 74
(3)
◽
pp. 121-126
1959 ◽
Vol 7
(3)
◽
pp. 306-310
◽
2010 ◽
Vol 30
(4)
◽
pp. 1291-1300
◽