Halmos, P. R. (1967). A Hilbert space problem book. D. Van Nostrand.
Cita Chicago (17th ed.)Halmos, Paul Richard. A Hilbert Space Problem Book. Princeton: D. Van Nostrand, 1967.
Cita MLA (9th ed.)Halmos, Paul Richard. A Hilbert Space Problem Book. D. Van Nostrand, 1967.
Atenció: Aquestes cites poden no estar 100% correctes.