Unified treatment and classification of superintegrable systems with   integrals quadratic in momenta on a two dimensional manifold
  In this paper we prove that the two dimensional superintegrable systems with quadratic integrals of motion on a manifold can be classified by using the Poisson algebra of the integrals of motion. There are six general fundamental classes of superintegrable systems. Analytic formulas for the involved integrals are calculated in all the cases. All the known superintegrable systems are classified as special cases of these six general classes. 
C. Daskaloyannis, K. Ypsilantis (Aristotle University of Thessaloniki)