PROF U C DE. W2-FLAT SPACETIME IN FRW COSMOLOGICAL MODEL. Journal of International Academy of Physical Sciences, [S. l.], v. 26, n. 3, p. 211–223, 2022. Disponível em: https://www.iaps.org.in/journal/index.php/journaliaps/article/view/949. Acesso em: 25 apr. 2025.