ANDREWS JR., H. N.; MAMAY, S. H. A brief conspectus of American Coal ball studies. Journal of Palaeosciences, [S. l.], v. 1, p. 66–72, 1952. DOI: 10.54991/jop.1952.373. Disponível em: https://jpsonline.co.in/index.php/jop/article/view/373. Acesso em: 14 may. 2024.