CALDAS, José Vaz; REBELO, João. Technical efficiency and productivity growth in the farming system of the douro region: a stochastic frontier approach. Douro : Estudos & Documentos, [S. l.], n. 15, 2022. Disponível em: http://84.247.136.72/ojsletrasX/index.php/dou/article/view/12642. Acesso em: 29 jul. 2025.