APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

Helmberg, Gilbert. Introduction to Spectral Theory in Hilbert Space. Amsterdam [u.a.]: North-Holland, 1969.

MLA (9th ed.) Citation

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

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