Holdau-Willems, G. (1998). Abschied von Opa: Gisela Holdau-Willems. Patmos.
Cita Chicago (17th ed.)Holdau-Willems, Gisela. Abschied Von Opa: Gisela Holdau-Willems. Düsseldorf: Patmos, 1998.
Cita MLA (8th ed.)Holdau-Willems, Gisela. Abschied Von Opa: Gisela Holdau-Willems. Patmos, 1998.
Atenció: Aquestes cites poden no estar 100% correctes.