@article{SIGMA_2013_9_a56,
     author = {Ernest G. Kalnins and Willard Miller Jr. and Sarah Post},
     title = {Contractions of {2D} 2nd {Order} {Quantum} {Superintegrable} {Systems} and the {Askey} {Scheme} for {Hypergeometric} {Orthogonal} {Polynomials}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2013},
     volume = {9},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2013_9_a56/}
}