Cita APA (7th ed.)
Hofstaetter, P. R. Warum? - Warum nicht?
Cita Chicago (17th ed.)
Hofstaetter, Peter Robert. Warum? - Warum Nicht?
Cita MLA (9th ed.)
Hofstaetter, Peter Robert. Warum? - Warum Nicht?
Atenció: Aquestes cites poden no estar 100% correctes.