@article {BertoldiADV,
	title = {Negative Poisson{\textquoteright}s ratio behavior induced by an elastic instability},
	journal = {Advanced Materials},
	volume = {22},
	year = {2010},
	pages = {361-366},
	author = {Bertoldi, K. and Reis, P.M. and Willshaw, S. and Mullin, T.}
}
