Cita APA (7th ed.)

Petzoldt, R. (1963). Richard Wagner. Verlag Enzyklopädie.

Cita Chicago (17th ed.)

Petzoldt, Richard. Richard Wagner. Leipzig: Verlag Enzyklopädie, 1963.

Cita MLA (8th ed.)

Petzoldt, Richard. Richard Wagner. Verlag Enzyklopädie, 1963.