@article {357501, title = {Hierarchical honeycomb auxetic metamaterials}, journal = {Scientific Reports}, volume = {5}, year = {2015}, pages = {18306 }, author = {Davood Mousanezhad and Sahab Babaee and Hamid Ebrahimi and Ranajay Ghosh and Abdelmagid Salem Hamouda and Katia Bertoldi and Ashkan Vaziri} }