ROMELL, L. G.; HEIBERG, S. O. Types of Humus Layer in the Forests of North-Eastern United States. Indian Forester, [S. l.], v. 57, n. 12, p. 627–628, 1931. DOI: 10.36808/if/1931/v57i12/20042. Disponível em: http://indianforester.co.in/index.php/indianforester/article/view/20042. Acesso em: 4 dec. 2025.