Lewis, D. C. Periodic solutions of differential equations containing a parameter. (English) Zbl 0068.30006 Duke Math. J. 22, 39-56 (1955). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 1 Document Keywords:Ordinary differential equations PDF BibTeX XML Cite \textit{D. C. Lewis}, Duke Math. J. 22, 39--56 (1955; Zbl 0068.30006) Full Text: DOI OpenURL