LAUGESEN, R.S.; WATSON, N. A. Another way to say subsolution: the maximum principle and sums of Green functions. Mathematica Scandinavica, Berkeley, CA, United States, v. 97, n. 1, p. 127–153, 2005. DOI: 10.7146/math.scand.a-14968. Disponível em: https://journals.msp.org/mscand/article/view/729. Acesso em: 25 jul. 2026.