An analytical hierarchical model explaining the robustness and flaw-tolerance of the interlocking barb-barbule structure of bird feathersQiang Chen, Stanislav Gorb, Alexander Kovalev, Zhiyong Li and Nicola PugnoEPL, 116 2 (2016) 24001DOI: https://doi.org/10.1209/0295-5075/116/24001