GÜLER, E. Hypersphere and the fourth Laplace-Beltrami operator in 4-space. Malaya Journal of Matematik, India, v. 11, n. 01, p. 1–10, 2023. DOI: 10.26637/mjm1101/001. Disponível em: https://www.malayajournal.org/index.php/mjm/article/view/38. Acesso em: 20 may. 2024.