Optimization of the double-span purlins design sketch in a framework with portal frames through the rafter stays application. Academic journal Industrial Machine Building Civil Engineering, [S. l.], v. 1, n. 56, p. 30–36, 2022. DOI: 10.26906/znp.2021.56.2504. Disponível em: https://ojs35.nupp.edu.ua/znp/article/view/2504. Acesso em: 23 dec. 2025.