HEILKER, T.; SIEG, G. A duopoly of transportation network companies and traditional radio-taxi dispatch service agencies. European Journal of Transport and Infrastructure Research, [S. l.], v. 18, n. 2, 2018. DOI: 10.18757/ejtir.2018.18.2.3230. Disponível em: https://journals.open.tudelft.nl/ejtir/article/view/3230. Acesso em: 3 dec. 2021.