AGTERBERG, F. P.; GRADSTEIN, F. M.; GALE, A. Estimation of the ages of Devonian and Cretaceous stage boundaries in the Geologic Time Scale. Boletín Geológico y Minero, [S. l.], v. 131, n. 2, p. 309–323, 2020. DOI: 10.21701/bolgeomin.131.2.006. Disponível em: https://bgm.revistas.csic.es/index.php/bgm/article/view/134. Acesso em: 3 may. 2025.