APOSTOL, B. F. Vibration eigenfrequencies of an elastic sphere with large radius. Annals of Mathematics and Physics, [S. l.], v. 7, n. 2, p. 138–147, 2024. DOI: 10.17352/amp.000116. Disponível em: https://www.peertechzpublications.us/amp/article/view/AMP-7-216. Acesso em: 10 jan. 2025.