A geometrical method towards first integrals for dynamical systems
  We develop a method, based on Darboux' and Liouville's works, to find first integrals and/or invariant manifolds for a physically relevant class of dynamical systems, without making any assumption on these elements' form. We apply it to three dynamical systems: Lotka--Volterra, Lorenz and Rikitake. 
Simon Labrunie and Robert Conte (Service de physique de l'\'etat   condens\'e, CEA Saclay, Gif-sur-Yvette, France)