STØRMER, Erling. Extension of positive maps. MATHEMATICA SCANDINAVICA, [S. l.], v. 126, n. 2, p. 256–258, 2020. DOI: 10.7146/math.scand.a-115974. Disponível em: https://tidsskrift.dk/math/article/view/115974. Acesso em: 14 aug. 2026.