Koch, H., Wassilieff, W., & Zimmermann, K. Grau-Eule. Progress.
Cita Chicago (17th ed.)Koch, H., W. Wassilieff, i Kurt Zimmermann. Grau-Eule. Moskau: Progress.
Cita MLA (8th ed.)Koch, H., et al. Grau-Eule. Progress.
Atenció: Aquestes cites poden no estar 100% correctes.