APA (7th ed.) Citation

Helmberg, G. (1969). Introduction to spectral theory in Hilbert space. North-Holland Pub. Co. Wiley.

Chicago Style (17th ed.) Citation

Helmberg, Gilbert. Introduction to Spectral Theory in Hilbert Space. Amsterdam London: North-Holland Pub. Co. Wiley, 1969.

MLA (9th ed.) Citation

Helmberg, Gilbert. Introduction to Spectral Theory in Hilbert Space. North-Holland Pub. Co. Wiley, 1969.

Warning: These citations may not always be 100% accurate.