SORJONEN, P. On linear relations in an indefinite inner product space. Annales Fennici Mathematici, [S. l.], v. 4, n. 1, p. 169–192, 1979. DOI: 10.5186/aasfm.1978-79.0424. Disponível em: https://afm.journal.fi/article/view/134346. Acesso em: 25 nov. 2024.