Bacigalupo, Andrea and Gnecco, Giorgio and Lepidi, Marco and Gambarotta, Luigi  Design of acoustic metamaterials through nonlinear programming.   In:  Machine Learning, Optimization, and Big Data. Second International Workshop, MOD 2016, Volterra, Italy, August 26-29, 2016, Revised Selected Papers.   Lecture Notes in Computer Science  (10122).  Springer, pp. 170-181.  ISBN 978-3-319-51468-0      (2016)