Buckling along boundaries of elastic contrast as a mechanism for early vertebrate morphogenesis Vincent Fleury, Nicolas R. Chevalier, Fabien Furfaro and Jean-Loup Duband Eur. Phys. J. E, 38 2 (2015) 6 Published online: 12 February 2015 DOI: 10.1140/epje/i2015-15006-7