AHMED, K. M.; RAKNUZZAMAN, M.; ALI, M. S. On Some Characterizations of Vector Fields on Manifolds. Dhaka University Journal of Science, [S. l.], v. 60, n. 2, p. 259–263, 2012. DOI: 10.3329/dujs.v60i2.11530. Disponível em: https://banglajol.info/index.php/DUJS/article/view/11530. Acesso em: 16 aug. 2024.