1. Mazzanti, A., Chiarucci, M., Prati, L., Bentley, K. W. & Wolf, C. J. Org. Chem. 81, 89–99 (2016).
2. Principe, L. Nature 469, 30–31 (2011).
3. Huygens, C. Oeuvres Complètes de Christiaan Huygens Vol. 5 (Martinus Nijhoff, 1893).
4. Serrin, J. in Contemporary Developments in Continuum Mechanics and Partial Differential Equations (eds de La Penha, G. M. & Medeiros, L. A. J.) 416 (North Holland Publishing Co, 1978).
5. Spiral thermometers Museo Galileo;
http://go.nature.com/H2u94w