VACHAL, K.; BITZAN, J.; BUTTON, K. Transportation quality indices for economic analysis of non-metropolitan cities. European Journal of Transport and Infrastructure Research, [S. l.], v. 7, n. 2, 2007. DOI: 10.18757/ejtir.2007.7.2.3381. Disponível em: https://journals.open.tudelft.nl/ejtir/article/view/3381. Acesso em: 1 apr. 2023.