Buonanno, Paolo; Durante, Ruben; Prarolo, Giovanni and Vanin, Paolo (2011): On the historical and geographic origins of the Sicilian mafia. Unpublished.
Michalopoulos, Stelios; Naghavi, Alireza and Prarolo, Giovanni (2010): Trade and Geography in the Economic Origins of Islam: Theory and Evidence. Unpublished.