An historical survey of ordinary linear differential equations with a large parameter and turning points
1971 ◽
Vol 7
(4)
◽
pp. 277-324
◽
1959 ◽
Vol 7
(3)
◽
pp. 306-310
◽
1986 ◽
Vol 41
(1)
◽
pp. 221-222
◽
1984 ◽
Vol 29
(4)
◽
pp. 309-376
◽