(1951). Wat is P.B.O.? De Steeg.
Chicago Style (17th ed.) CitationWat Is P.B.O.? De Steeg, 1951.
MLA (8th ed.) CitationWat Is P.B.O.? De Steeg, 1951.
Warning: These citations may not always be 100% accurate.
APA (7th ed.) Citation