TANNOUS, Edward. Gravitational Energy Levels: Part Two. Journal of natural sciences, life and applied sciences, New Mexico, United States, v. 5, n. 4, p. 62–47, 2021. DOI: 10.26389/AJSRP.S190721. Disponível em: https://www.ajsrp.ojsexpert.com/index.php/jnslas/article/view/4432. Acesso em: 19 dec. 2025.