TEXTORIUS, B. Minimaxprinzipe zur Bestimmung der Eigenwerte $J$-nichtnegativer Operatoren. MATHEMATICA SCANDINAVICA, [S. l.], v. 35, p. 105–114, 1974. DOI: 10.7146/math.scand.a-11538. Disponível em: https://www.mscand.dk/article/view/11538. Acesso em: 24 nov. 2024.