“…They first considered quadratic superintegrability in Euclidean spaces and the subject has been subsequently developed into many directions by several authors since then. For example, its close relation with multiseparability was studied in detail in the references [17,18,20,31,42,49], the search for superintegrable systems in 2-and 3-dimensional spaces of constant and nonconstant curvature has been carried out in the works [25,26,27,31,32,33,35,36,37,50] and their generalizations to n-dimensions have been analyzed in the papers [38,39,59].…”