Rafael Medoff; Chaim I. Waxman, eds. (2000). Historical Dictionary of Zionism. Routledge. pp. 66-67, 163. ISBN978-1-57958-286-9. Consultado el 20 de marzo de 2015. «Gruenbaum was the leader of the Radical Zionists, known in Poland as Al Hamishmar».
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dx.doi.org
Glasner-Heled, Galia; Bar-On, Dan (2009). «Displaced: The Memoir of Eliezer Gruenbaum, Kapo at Birkenau—Translation and Commentary». Shofar27 (2): 1-23. doi:10.1353/sho.0.0222.