YLINEN, K. Measures of noncompactness for elements of C*-algebras. Annales Fennici Mathematici, [S. l.], v. 6, n. 1, p. 131–133, 1981. DOI: 10.5186/aasfm.1981.0627. Disponível em: https://afm.journal.fi/article/view/134404. Acesso em: 14 apr. 2025.