Papa, Enrica. “Subway and Skyway System: Sustainable Infrastructure for Walking?”. TeMA - Journal of Land Use, Mobility and Environment 1, no. 3 (December 2, 2008). Accessed March 28, 2024. http://www.serena.unina.it/index.php/tema/article/view/urn%3Anbn%3Ait%3Aunina-3568.