Rafael Medoff; Chaim I. Waxman, eds. (2000). Historical Dictionary of Zionism. Routledge. pp. 66–67, 163. ISBN978-1-57958-286-9. Retrieved 20 March 2015. Gruenbaum was the leader of the Radical Zionists, known in Poland as Al Hamishmar
Glasner-Heled, Galia; Bar-On, Dan (2009). "Displaced: The Memoir of Eliezer Gruenbaum, Kapo at Birkenau—Translation and Commentary". Shofar. 27 (2): 1–23. doi:10.1353/sho.0.0222. JSTOR42944445. S2CID145298849.
Glasner-Heled, Galia; Bar-On, Dan (2009). "Displaced: The Memoir of Eliezer Gruenbaum, Kapo at Birkenau—Translation and Commentary". Shofar. 27 (2): 1–23. doi:10.1353/sho.0.0222. JSTOR42944445. S2CID145298849.
Glasner-Heled, Galia; Bar-On, Dan (2009). "Displaced: The Memoir of Eliezer Gruenbaum, Kapo at Birkenau—Translation and Commentary". Shofar. 27 (2): 1–23. doi:10.1353/sho.0.0222. JSTOR42944445. S2CID145298849.