Leighton, Walter Principal quadratic functionals and self-adjoint second-order differential equations. (English) Zbl 0032.34603 Proc. Natl. Acad. Sci. USA 35, 192-193 (1949). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 3 Documents Keywords:Ordinary differential equations × Cite Format Result Cite Review PDF Full Text: DOI Link