BARKOFF, E. Beiträge zur kalorimetrischen Humusbestimmung im Boden. Agricultural and Food Science, [S. l.], v. 26, n. 1, p. 198–210, 1954. DOI: 10.23986/afsci.71360. Disponível em: https://journal.fi/afs/article/view/71360. Acesso em: 18 apr. 2025.