ArticleNecessary Conditions for an ExtremumE. Polak·B. N. Pshenichnyĭ·1972·enABIABI:AkademIndex/openalex/2026.other.615435CiteAbstractNo abstract available.IdentifiersDOI10.2307/2005191Citations and referencesCited by 20 referencesMetrics — AkademScholar