On the differential equation {$(x+\varepsilon u)\,du/dx+q(x)u-r(x)=0$}

MR0209597 Sibuya, Yasutaka and Takahasi, Ken-iti Yasutaka SIBUYA and Ken-iti TAKAHASI On the differential equation {$(x+\varepsilon u)\,du/dx+q(x)u-r(x)=0$} Funkcialaj Ekvacioj. Serio Internacia 9 1966 71--81 http://fe.math.kobe-u.ac.jp/FE/Free/vol09/fe09-14.pdf http://fe.math.kobe-u.ac.jp/FE/FE_pdf_with_bookmark/FE01-10-en_KML/fe09-071-081/fe09-071-081.pdf http://www.ams.org/mathscinet-getitem?mr=MR0209597 fe09-071-081 1966 On the Differential Equation $(x+\epsilon u)du/dx+q(x)u-r(x)=0$. SIBUYA, Yasutaka; TAKAHASI, Ken-iti SIBUYA, Yasutaka; TAKAHASI, Ken-iti

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