@article{ZNSL_1976_62_a17,
     author = {Z. A. Yanson},
     title = {Asymptotics of solutions of second-order differential equations with two turning points and a complex {parameter.~I}},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {220--233},
     year = {1976},
     volume = {62},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1976_62_a17/}
}