@Article{ SoaTer18, author = { Soave, Nicola and Terracini, Susanna }, title = { The nodal set of solutions to some elliptic problems: sublinear equations, and unstable two-phase membrane problem }, journal = { Advances in Mathematics }, year = { 2018 }, volume = { 334 }, pages = { }, URL = { http://cvgmt.sns.it/paper/4209/ }, note = { cvgmt preprint} }