APA (7th ed.) Citation

Halmos, P. R. (1967). A Hilbert space problem book. D. Van Nostrand.

Chicago Style (17th ed.) Citation

Halmos, Paul Richard. A Hilbert Space Problem Book. Princeton: D. Van Nostrand, 1967.

MLA (9th ed.) Citation

Halmos, Paul Richard. A Hilbert Space Problem Book. D. Van Nostrand, 1967.