PORTO, C. M.; PULVIRENTI, T. Technological Clusters And Territorial Competitiveness In Southern Urban System. The "Etna Valley" Experience in Catania. Bollettino della Società Geografica Italiana, [S. l.], p. 587–614, 2012. DOI: 10.36253/bsgi-7393. Disponível em: https://www.bsgi.it/index.php/bsgi/article/view/7393. Acesso em: 6 oct. 2026.