Kalnins, E.G.; Miller Jr., W.; Post, S.
(Symmetry, Integrability and Geometry: Methods and Applications, 2013)
We show explicitly that all 2nd order superintegrable systems in 2 dimensions are limiting cases of a single system: the generic 3-parameter potential on the 2-sphere, S9 in our listing. We extend the Wigner-Inönü method ...