Green's formula and the homeomorphism theorem for general elliptic boundary value problems with boundary conditions that are not normal
English version (Springer): Ukrainian Mathematical Journal 21 (1969), no. 3, pp 343-349.
Citation Example: Roitberg Ya. A. Green's formula and the homeomorphism theorem for general elliptic boundary value problems with boundary conditions that are not normal // Ukr. Mat. Zh. - 1969. - 21, № 3. - pp. 406–413.
Full text