Ritter, J. (1989). P - Q. Schwabe.
Cita Chicago (17th ed.)Ritter, Joachim. P - Q. Basel: Schwabe, 1989.
Cita MLA (8th ed.)Ritter, Joachim. P - Q. Schwabe, 1989.
Atenció: Aquestes cites poden no estar 100% correctes.
Cita APA (7th ed.)