ESSÉN, M.; SHEA, D. F. On some questions of uniqueness in the theory of symmetrization. Annales Fennici Mathematici, [S. l.], v. 4, n. 2, p. 311–340, 1979. DOI: 10.5186/aasfm.1978-79.0404. Disponível em: https://afm.journal.fi/article/view/134357. Acesso em: 25 nov. 2024.