1. Abou-Chadi, T., Mitteregger, R., & Mudde, C. (2021). Left behind by the working class? Social democracy’s electoral crisis and the rise of the radical right. Friedrich-Ebert-Stiftung.
2. Amann, M., Fichtner, U., Großbongardt, A., Hagen, K., Knobbe, M., Rapp, T., & Reimann, A. (2022). Die Sinnkrise der Sozialdemokraten. Der Spiegel, 17. https://www.spiegel.de/politik/spd-und-der-ukraine-krieg-die-sinnkrise-der-sozialdemokratie-a-62a00e8e-6861-4605-ae3d-7757858efeef. Zugegriffen: 11. Aug. 2022.
3. Bértoa, F. C., & Enyedi, Z. (2021). Party system closure. Party alliances, government alternatives, and democracy in Europe. Oxford University Press.
4. Bremer, B. (2020). The political economy of the SPD reconsidered: Evidence from the Great recession. German Politics, 29(3), 441–463.
5. Bremer, B., & Rennwald, L. (2022). Who still likes social democracy? The support base of social democratic parties reconsidered. Party Politics, Online first.