Die Linke in der SPD. PROKLA. Journal of Critical Social Science, Berlin, DE, v. 7, n. 28, p. 57–107, 1977. DOI: 10.32387/prokla.v7i28.1686. Disponível em: https://prokla.de/index.php/PROKLA/article/view/1686. Acesso em: 11 jan. 2026.