Bruno Mugnai, I volontari stranieri e le brigate internazionali in Spagna (1936--1939): Foreign Volunteers and International Brigades in Spain (1936--39) (Zanica, Italy: Soldiershop Publishing, 2010), 17; Giulietti, Il movimento anarchico italiano, 245--46 n. 551; David Berry, "French Anarchist Volunteers in Spain, 1936--1939: Contribution to a Collective Biography of the French Anarchist Movement," Research on Anarchism, 1997, http://
Mario Gianfrate and Kenyon Zimmer, Michele Centrone, tra vecchio e nuovo mondo: Anarchici pugliesi in difesa della liberta' spagnola (Sammichele di Bari, Italy: SUMA Editore, 2012); Umberto Marzocchi, Remembering Spain: Italian Anarchist Volunteers in the Spanish Civil War, trans.