Y. Grandati, A. Bérard, H. Mohrbach, “Complex Representation of Planar Motions and Conserved Quantities of the Kepler and Hooke Problems”, JNMP, 17:2 (2021), 213
A.V. Tsiganov, “The Maupertuis Principle and Canonical Transformations of the Extended Phase Space”, JNMP, 8:1 (2001), 157
A V Tsiganov, “Properties of the canonical transformations of the time for the Toda lattice and the Henon-Heiles system”, J. Phys. A: Math. Gen., 33:26 (2000), 4825