El'sgol'ts, L. E., & El'sgol'ts, L. E. (1970). Differential equations and the calculus of variations. Moscow: Mir.
Chicago Style CitationEl'sgol'ts, Levi Ernestovich, and Levi Ernestovich El'sgol'ts. Differential Equations and the Calculus of Variations. Moscow: Mir, 1970.
MLA CitationEl'sgol'ts, Levi Ernestovich, and Levi Ernestovich El'sgol'ts. Differential Equations and the Calculus of Variations. Moscow: Mir, 1970.
Warning: These citations may not always be 100% accurate.