“…These externalities reflect the result of complex interactions among different sources, hence obtaining controls for all these effects is a challenge (Rosenthal & Strange, 2004). Most models to identify agglomeration effects therefore use one or two of the key aspects of scope, for example, Glaeser et al (1992), Henderson et al (1995), Henderson (1997Henderson ( , 2003, Combes (2000), Ciccone (2002), Combes, Magnac, and Robin (2004), Rosenthal and Strange (2003), Blien, Suedekum, and Wolf (2006), Paci and Usai (2008), Graham (2009), Marrocu, Paci, and Usai (2012), Mameli, Faggian, and McCann (2014), Kemeny and Storper (2015), Caragliu, de Dominicis, and Groot (2016), Camagni, Capello, and Caragliu (2016) and Barufi, Haddad, and Nijkamp (2016), with the exception of Dauth (2013) who added all three effects.…”