Uniform asymptotic solutions of boundary and eigenvalue problems for a second-order ordinary differential equation with singular and turning pointsDONATUS UZODINMA ANYANWU.Journal of mathematical analysis and applications. 1988, Vol 134, Num 2, pp 379-395, issn 0022-247XArticle

Uniform asymptotic solutions of second-order linear ordinary differential equations with singular points. I: Formal theoryDONATUS UZODINMA ANYANWU.Journal of mathematical analysis and applications. 1988, Vol 134, Num 2, pp 329-354, issn 0022-247XArticle

Uniform asymptotic solutions of second-order linear ordinary differential equations with singular points. II: Some expansionsDONATUS UZODINMA ANYANWU.Journal of mathematical analysis and applications. 1988, Vol 134, Num 2, pp 355-378, issn 0022-247XArticle