JAYA UPRETI AND SHANKAR LA. Cartesian Product of r-GF Structure Manifolds. Journal of International Academy of Physical Sciences, [S. l.], v. 13, n. 3, p. 293–298, 2009. Disponível em: https://www.iaps.org.in/journal/index.php/journaliaps/article/view/194. Acesso em: 18 may. 2024.