S. B. PANDEY, M. PANT. Hyperbolic R Π Structure Manifold. Journal of International Academy of Physical Sciences, [S. l.], v. 8, n. 1-4, p. 85–97, 2004. Disponível em: https://www.iaps.org.in/journal/index.php/journaliaps/article/view/786. Acesso em: 11 may. 2025.