Second order equations with nonnegative characteristic form - Oleinik, O. A.; Radkevich, E. V. (Evgenii Vladimirovich). (Providence, R.I.: American Mathematical Society, 1973)
Translation of Uravneniia vtorogo poriadka s neotritsatelnoi kharakteristicheskoi formoi.
Bibliography: p. 251-259.
engrus.
Keywords: Differential equations, Partial; Boundary value problems