AGARD, Stephen; FEHLMANN, Richard. On the extremality and unique extremality of affine mappings in space, an addendum. Annales Fennici Mathematici, [S. l.], v. 12, n. 2, p. 299–301, 1987. DOI: 10.5186/aasfm.1987.1201. Disponível em: https://afm.journal.fi/article/view/134605. Acesso em: 13 apr. 2026.