International differential pricing: easy in theory but hard in practice. Farmeconomia. Health economics and therapeutic pathways, [S. l.], v. 14, n. 3, p. 107–109, 2013. DOI: 10.7175/fe.v14i3.648. Disponível em: https://journals.seedstm.com/index.php/FE/article/view/648. Acesso em: 29 oct. 2025.