LÖFSTRÖM, J. On Certain Interpolation Spaces Related to Generalized Semi-Groups. MATHEMATICA SCANDINAVICA, [S. l.], v. 16, p. 41–54, 1965. DOI: 10.7146/math.scand.a-10747. Disponível em: https://www.mscand.dk/article/view/10747. Acesso em: 7 may. 2024.