Nehari Extremal problems for a class of functionals defined on convex sets Mathematics Technical Report Convex sets.;Eigenvalues.;Functionals. 1966-01-01
    https://kilthub.cmu.edu/articles/journal_contribution/Extremal_problems_for_a_class_of_functionals_defined_on_convex_sets/6477419
10.1184/R1/6477419.v1