Cita APA (7a ed.)

FREDRICHS K O. (1965). PERTURBATION OF SPECTRA IN HELBERT SPACE. -.

Cita Chicago Style (17a ed.)

FREDRICHS K O. PERTURBATION OF SPECTRA IN HELBERT SPACE. -: -, 1965.

Cita MLA (9a ed.)

FREDRICHS K O. PERTURBATION OF SPECTRA IN HELBERT SPACE. -, 1965.