PENN, A. . Conveyor system solves loading problem. Materiales de Construcción, [S. l.], n. 018, p. 15–15, 1950. DOI: 10.3989/mc.1950.i018.3192. Disponível em: https://materconstrucc.revistas.csic.es/index.php/materconstrucc/article/view/3192. Acesso em: 6 may. 2024.