@conference {NaBIC2011, title = {Solving the Node Localization Problem in WSNs by a Two-objective Evolutionary Algorithm and Gradient Descent}, booktitle = {the 3-th IEEE World Congress on Nature and Biologically Inspired Computing (NaBIC 2011)}, year = {2011}, author = {Massimo Vecchio and R. L{\'o}pez-Valcarce and Francesco Marcelloni} }