NYSTRÖM, Kaj. Regularity below the continuous threshold in a two-phase parabolic free boundary problem. Mathematica Scandinavica, Berkeley, CA, United States, v. 99, n. 2, p. 257–286, 2006. DOI: 10.7146/math.scand.a-15012. Disponível em: https://journals.msp.org/mscand/article/view/685. Acesso em: 24 jul. 2026.