Gellert, W. (1963). Natur. Enzyklopädie.
Cita Chicago (17th ed.)Gellert, Walter. Natur. Leipzig: Enzyklopädie, 1963.
Cita MLA (8th ed.)Gellert, Walter. Natur. Enzyklopädie, 1963.
Atenció: Aquestes cites poden no estar 100% correctes.
Cita APA (7th ed.)