GAARDE, Anders; GRUBB, Gerd. Logarithms and sectorial projections for elliptic boundary problems. Mathematica Scandinavica, Berkeley, CA, United States, v. 103, n. 2, p. 243–277, 2008. DOI: 10.7146/math.scand.a-15079. Disponível em: https://journals.msp.org/mscand/article/view/618. Acesso em: 8 sep. 2026.