(EN) Tamir Bar-On, Where Have All the Fascists Gone?, Ashgate Publishing, Ltd., 1º gennaio 2007, p. 39, ISBN 978-0-7546-7154-1. URL consultato il 28 agosto 2026.
«a similar strategy of infiltration within the military milieu by Italian radical right-wing terrorist groups and clandestine elite pressure groups such as Propaganda-Due (P-2)»