Correa, D., Poppinga, S., Mylo, M., Westermeier, A., Bruchmann, B., Menges, A., Speck T.: 2020, 4D pine scale: biomimetic 4D printed autonomous scale and flap structures capable of multi-phase movement, Philosophical Transactions A, 378, pp. 20190445. (doi: 10.1098/rsta.2019.0445)