On the Steklov problem in a domain perforated along a part of the boundary Gregory A. Chechkin, Rustem R. Gadyl’shin, Ciro D’Apice and Umberto De Maio ESAIM: M2AN, 51 4 (2017) 1317-1342 Published online: 21 July 2017 DOI: 10.1051/m2an/2016063