Hofer, H., Wysocki, K. and Zehnder, E. (1996) “Unknotted periodic orbits for Reeb flows on the three-sphere”, Topological Methods in Nonlinear Analysis, 7(2), pp. 219–244. Available at: https://apcz.umk.pl/TMNA/article/view/TMNA.1996.010 (Accessed: 22 July 2024).